<86>Apr 16 11:11:17 userdel[1446513]: delete user 'rooter'
<86>Apr 16 11:11:17 userdel[1446513]: removed group 'rooter' owned by 'rooter'
<86>Apr 16 11:11:17 userdel[1446513]: removed shadow group 'rooter' owned by 'rooter'
<86>Apr 16 11:11:17 groupadd[1446519]: group added to /etc/group: name=rooter, GID=705
<86>Apr 16 11:11:17 groupadd[1446519]: group added to /etc/gshadow: name=rooter
<86>Apr 16 11:11:17 groupadd[1446519]: new group: name=rooter, GID=705
<86>Apr 16 11:11:17 useradd[1446526]: new user: name=rooter, UID=705, GID=705, home=/root, shell=/bin/bash
<86>Apr 16 11:11:17 userdel[1446532]: delete user 'builder'
<86>Apr 16 11:11:17 userdel[1446532]: removed group 'builder' owned by 'builder'
<86>Apr 16 11:11:17 userdel[1446532]: removed shadow group 'builder' owned by 'builder'
<86>Apr 16 11:11:17 groupadd[1446542]: group added to /etc/group: name=builder, GID=706
<86>Apr 16 11:11:17 groupadd[1446542]: group added to /etc/gshadow: name=builder
<86>Apr 16 11:11:17 groupadd[1446542]: new group: name=builder, GID=706
<86>Apr 16 11:11:17 useradd[1446550]: new user: name=builder, UID=706, GID=706, home=/usr/src, shell=/bin/bash
/usr/src/in/srpm/libgconfmm2-2.28.3-alt1.src.rpm: The use of such a license name is ambiguous: LGPL
warning: user aris does not exist - using root
warning: group aris does not exist - using root
warning: user aris does not exist - using root
warning: group aris does not exist - using root
warning: user aris does not exist - using root
warning: group aris does not exist - using root
<13>Apr 16 11:11:24 rpmi: libsigc++2-2.10.6-alt1 sisyphus+262543.100.1.1 1606332557 installed
<13>Apr 16 11:11:24 rpmi: libexpat-2.2.10-alt1 sisyphus+259966.100.1.1 1602824518 installed
<13>Apr 16 11:11:24 rpmi: xorg-proto-devel-2020.1-alt1 sisyphus+250406.100.1.1 1587554810 installed
<13>Apr 16 11:11:24 rpmi: libsigc++2-devel-2.10.6-alt1 sisyphus+262543.100.1.1 1606332557 installed
<13>Apr 16 11:11:24 rpmi: perl-HTTP-Date-6.05-alt1 sisyphus+258981.100.1.1 1601542386 installed
<13>Apr 16 11:11:24 rpmi: libglvnd-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:24 rpmi: libpng16-1.6.37-alt1 sisyphus+236677.100.2.1 1566917998 installed
<13>Apr 16 11:11:24 rpmi: libnettle8-3.7.2-alt1 sisyphus+268184.100.1.1 1616430275 installed
<13>Apr 16 11:11:24 rpmi: zlib-devel-1.2.11-alt1 sisyphus+221902.6000.4.1 1550601058 installed
<13>Apr 16 11:11:24 rpmi: perl-LWP-MediaTypes-6.04-alt1 sisyphus+225468.100.1.1 1553186684 installed
<13>Apr 16 11:11:24 rpmi: perl-Compress-Raw-Zlib-2.101-alt1 sisyphus+266765.100.1.2 1614138847 installed
<13>Apr 16 11:11:24 rpmi: perl-libnet-1:3.13-alt1 sisyphus+266120.100.1.1 1612961310 installed
<13>Apr 16 11:11:24 rpmi: libXau-1.0.9-alt1 sisyphus+223149.200.2.1 1551268152 installed
<13>Apr 16 11:11:24 rpmi: libwayland-server-1.19.0-alt1 sisyphus+265427.100.1.1 1611852858 installed
<13>Apr 16 11:11:25 rpmi: libjpeg-2:2.0.6-alt1 sisyphus+266888.100.1.1 1614172387 installed
<13>Apr 16 11:11:28 rpmi: libicu67-1:6.7.1-alt2 sisyphus+252432.100.2.2 1590796126 installed
<13>Apr 16 11:11:28 rpmi: libgraphite2-1.3.14-alt2 sisyphus+250009.100.1.1 1586943065 installed
<13>Apr 16 11:11:28 rpmi: libp11-kit-0.23.15-alt2 sisyphus+252784.100.2.2 1591274901 installed
<13>Apr 16 11:11:28 rpmi: libtasn1-4.16.0-alt1 sisyphus+245480.100.1.1 1580825062 installed
<13>Apr 16 11:11:28 rpmi: libgraphite2-devel-1.3.14-alt2 sisyphus+250009.100.1.1 1586943065 installed
<13>Apr 16 11:11:28 rpmi: icu-utils-1:6.7.1-alt2 sisyphus+252432.100.2.2 1590796126 installed
<13>Apr 16 11:11:28 rpmi: libicu-devel-1:6.7.1-alt2 sisyphus+252432.100.2.2 1590796126 installed
<13>Apr 16 11:11:28 rpmi: libXau-devel-1.0.9-alt1 sisyphus+223149.200.2.1 1551268152 installed
<13>Apr 16 11:11:28 rpmi: libpng-devel-1.6.37-alt1 sisyphus+236677.100.2.1 1566917998 installed
<13>Apr 16 11:11:28 rpmi: libhogweed6-3.7.2-alt1 sisyphus+268184.100.1.1 1616430275 installed
<13>Apr 16 11:11:28 rpmi: libOpenGL-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:28 rpmi: libGLES-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:28 rpmi: perl-File-Listing-6.14-alt1 sisyphus+262735.100.1.1 1606813544 installed
<13>Apr 16 11:11:29 rpmi: libgtk+2-locales-2.24.33-alt1 sisyphus+263711.100.20.1 1609407991 installed
<13>Apr 16 11:11:29 rpmi: libfribidi-1.0.10-alt1 sisyphus+254557.100.1.1 1594020362 installed
<13>Apr 16 11:11:29 rpmi: libdatrie-0.2.9-alt1_6 1511686676 installed
<13>Apr 16 11:11:29 rpmi: libthai-0.1.28-alt1_1 sisyphus+226107.100.1.1 1554123079 installed
<13>Apr 16 11:11:29 rpmi: libidn2-2.3.0-alt1 sisyphus+240846.100.1.2 1573870475 installed
<13>Apr 16 11:11:30 rpmi: libgnutls30-3.6.15-alt2 sisyphus+268189.200.4.1 1616495163 installed
<13>Apr 16 11:11:30 rpmi: libpixman-3:0.40.0-alt1 sisyphus+250700.100.1.1 1587971055 installed
<13>Apr 16 11:11:30 rpmi: perl-Try-Tiny-0.30-alt1 1514318058 installed
<13>Apr 16 11:11:30 rpmi: perl-IO-Socket-IP-0.41-alt1 sisyphus+259012.100.1.2 1601553446 installed
<13>Apr 16 11:11:30 rpmi: perl-Compress-Raw-Bzip2-2.101-alt1 sisyphus+266764.100.1.2 1614138565 installed
<13>Apr 16 11:11:30 rpmi: perl-HTML-Tagset-3.20-alt2 1317725093 installed
<13>Apr 16 11:11:30 rpmi: perl-Filter-1.60-alt1 sisyphus+258375.300.14.2 1600904226 installed
<13>Apr 16 11:11:30 rpmi: perl-Encode-3.08-alt1 sisyphus+263440.100.1.1 1607955886 installed
<13>Apr 16 11:11:30 rpmi: perl-URI-5.09-alt1 sisyphus+267398.100.1.1 1614944505 installed
<13>Apr 16 11:11:30 rpmi: perl-IO-Compress-2.102-alt1 sisyphus+267295.100.1.1 1614764488 installed
<13>Apr 16 11:11:30 rpmi: perl-Net-HTTP-6.21-alt1 sisyphus+268278.100.1.1 1616563972 installed
<13>Apr 16 11:11:30 rpmi: perl-HTML-Parser-3.76-alt1 sisyphus+267397.100.1.3 1614945689 installed
<13>Apr 16 11:11:30 rpmi: perl-WWW-RobotRules-6.02-alt1 1329756211 installed
<13>Apr 16 11:11:30 rpmi: perl-Encode-Locale-1.05-alt1 1444608613 installed
<13>Apr 16 11:11:30 rpmi: perl-IO-HTML-1.004-alt1 sisyphus+258983.100.1.1 1601542619 installed
<13>Apr 16 11:11:30 rpmi: perl-HTTP-Message-6.29-alt1 sisyphus+267426.100.1.1 1615033749 installed
<13>Apr 16 11:11:30 rpmi: perl-HTTP-Cookies-6.10-alt1 sisyphus+264349.100.1.1 1609891183 installed
<13>Apr 16 11:11:30 rpmi: perl-HTTP-Negotiate-6.01-alt1 1329760563 installed
<13>Apr 16 11:11:30 rpmi: perl-Term-ANSIColor-5.01-alt1 sisyphus+244783.100.1.2 1579747505 installed
<13>Apr 16 11:11:30 rpmi: perl-Data-Dump-1.23-alt1 1444601978 installed
<13>Apr 16 11:11:30 rpmi: perl-libwww-6.53-alt1 sisyphus+267863.100.1.1 1615828994 installed
<13>Apr 16 11:11:30 rpmi: perl-XML-Parser-2.46-alt1 sisyphus+263451.100.1.1 1607958574 installed
<13>Apr 16 11:11:30 rpmi: libatk-locales-2.36.0-alt1 sisyphus+249208.100.1.1 1585840405 installed
<13>Apr 16 11:11:30 rpmi: libatk-2.36.0-alt1 sisyphus+249208.100.1.1 1585840406 installed
<13>Apr 16 11:11:30 rpmi: openldap-common-2.4.57-alt1 sisyphus+266287.100.1.1 1613244218 installed
<13>Apr 16 11:11:30 rpmi: libverto-0.3.2-alt1_1 sisyphus+268398.100.1.1 1616717462 installed
<13>Apr 16 11:11:30 rpmi: liblmdb-0.9.23-alt1 sisyphus+225277.100.2.1 1553001679 installed
<13>Apr 16 11:11:30 rpmi: libkeyutils-1.6.3-alt1 sisyphus+266061.100.1.1 1612919567 installed
<13>Apr 16 11:11:30 rpmi: libcom_err-1.45.6.0.24.af1a-alt1 sisyphus+262279.100.1.1 1606088229 installed
<13>Apr 16 11:11:30 rpmi: liblz4-1:1.9.3-alt1 sisyphus+262305.100.1.1 1606099167 installed
<13>Apr 16 11:11:30 rpmi: libgpg-error-1.41-alt4 sisyphus+264254.200.1.1 1609440111 installed
<13>Apr 16 11:11:30 rpmi: libgcrypt20-1.9.2-alt1 sisyphus+266496.100.1.1 1613559234 installed
<13>Apr 16 11:11:31 rpmi: libsystemd-1:247.3-alt2 sisyphus+266129.100.1.3 1613012672 installed
<13>Apr 16 11:11:31 rpmi: libdbus-1.12.18-alt1 sisyphus+252758.100.1.1 1591203693 installed
<13>Apr 16 11:11:31 rpmi: libavahi-0.8-alt1 sisyphus+255349.240.4.1 1595604514 installed
<13>Apr 16 11:11:31 rpmi: libcups-2.3.3-alt3.op2 sisyphus+268789.100.1.1 1617267118 installed
<13>Apr 16 11:11:31 rpmi: libxshmfence-1.3-alt1 sisyphus+223149.1000.2.1 1551268571 installed
<13>Apr 16 11:11:31 rpmi: libX11-locales-3:1.7.0-alt1 sisyphus+264667.100.1.2 1610655150 installed
<13>Apr 16 11:11:31 rpmi: libXdmcp-1.1.3-alt1 sisyphus+225206.600.1.2 1552949353 installed
<13>Apr 16 11:11:31 rpmi: libxcb-1.14-alt1 sisyphus+247358.200.1.3 1583854228 installed
<13>Apr 16 11:11:31 rpmi: libX11-3:1.7.0-alt1 sisyphus+264667.100.1.2 1610655170 installed
<13>Apr 16 11:11:31 rpmi: libXext-1.3.4-alt1 sisyphus+225206.700.1.2 1552949429 installed
<13>Apr 16 11:11:31 rpmi: libXrender-0.9.10-alt1 sisyphus+261890.100.1.1 1605595177 installed
<13>Apr 16 11:11:31 rpmi: libXfixes-5.0.3-alt1 sisyphus+226736.100.2.2 1554614841 installed
<13>Apr 16 11:11:34 rpmi: libxcb-devel-1.14-alt1 sisyphus+247358.200.1.3 1583854228 installed
<13>Apr 16 11:11:34 rpmi: libX11-devel-3:1.7.0-alt1 sisyphus+264667.100.1.2 1610655170 installed
<13>Apr 16 11:11:34 rpmi: libXrender-devel-0.9.10-alt1 sisyphus+261890.100.1.1 1605595177 installed
<13>Apr 16 11:11:34 rpmi: libXext-devel-1.3.4-alt1 sisyphus+225206.700.1.2 1552949429 installed
<13>Apr 16 11:11:34 rpmi: libXcursor-1.2.0-alt1 sisyphus+225206.400.1.2 1552949218 installed
<13>Apr 16 11:11:34 rpmi: libXrandr-1.5.2-alt1 sisyphus+225206.1300.1.2 1552949710 installed
<13>Apr 16 11:11:34 rpmi: libXxf86vm-1.1.4-alt2 1527672187 installed
<13>Apr 16 11:11:34 rpmi: libXi-1.7.10-alt1 sisyphus+232786.300.1.1 1561106978 installed
<13>Apr 16 11:11:34 rpmi: libXinerama-1.1.4-alt1 sisyphus+223149.300.2.1 1551268216 installed
<13>Apr 16 11:11:34 rpmi: libXcomposite-0.4.5-alt1 sisyphus+225206.300.1.2 1552949137 installed
<13>Apr 16 11:11:34 rpmi: libXdamage-1.1.5-alt1 sisyphus+225206.500.1.2 1552949286 installed
<13>Apr 16 11:11:34 rpmi: libwayland-client-1.19.0-alt1 sisyphus+265427.100.1.1 1611852858 installed
<13>Apr 16 11:11:34 rpmi: libpciaccess-1:0.16-alt1 sisyphus+234814.100.1.1 1563438291 installed
<13>Apr 16 11:11:34 rpmi: libdrm-1:2.4.105-alt1 sisyphus+269183.100.1.1 1617867189 installed
<13>Apr 16 11:11:34 rpmi: libGLX-mesa-4:21.0.2-alt1 sisyphus+269183.200.1.1 1617867532 installed
<13>Apr 16 11:11:34 rpmi: libGLX-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:35 rpmi: libGL-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:35 rpmi: libgbm-4:21.0.2-alt1 sisyphus+269183.200.1.1 1617867532 installed
<13>Apr 16 11:11:35 rpmi: libEGL-mesa-4:21.0.2-alt1 sisyphus+269183.200.1.1 1617867532 installed
<13>Apr 16 11:11:35 rpmi: libEGL-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:35 rpmi: libglvnd-devel-7:1.3.2-alt1 sisyphus+254610.100.1.1 1594124268 installed
<13>Apr 16 11:11:35 rpmi: libEGL-devel-4:21.0.2-alt1 sisyphus+269183.200.1.1 1617867532 installed
<13>Apr 16 11:11:35 rpmi: libGL-devel-4:21.0.2-alt1 sisyphus+269183.200.1.1 1617867532 installed
<13>Apr 16 11:11:35 rpmi: icon-theme-hicolor-0.17-alt2 sisyphus+248343.100.1.1 1584979043 installed
<13>Apr 16 11:11:35 rpmi: libwebp7-1.2.0-alt1 sisyphus+265504.100.2.1 1612122046 installed
<13>Apr 16 11:11:35 rpmi: libjbig-2.1-alt1 1401380926 installed
<13>Apr 16 11:11:35 rpmi: libtiff5-4.2.0-alt1 sisyphus+266365.100.2.1 1613478695 installed
<13>Apr 16 11:11:35 rpmi: shared-mime-info-2.1-alt1 sisyphus+264261.100.1.1 1609507723 installed
<13>Apr 16 11:11:35 rpmi: libgdk-pixbuf-locales-2.42.6-alt1 sisyphus+269312.100.1.1 1617990309 installed
<13>Apr 16 11:11:35 rpmi: gsettings-desktop-schemas-data-40.0-alt1 sisyphus+268501.300.4.2 1617041783 installed
<13>Apr 16 11:11:35 rpmi: libgio-2.68.1-alt1 sisyphus+269248.100.1.1 1617921065 installed
<13>Apr 16 11:11:35 rpmi: gsettings-desktop-schemas-40.0-alt1 sisyphus+268501.300.4.2 1617041559 installed
<13>Apr 16 11:11:35 rpmi: libgdk-pixbuf-2.42.6-alt1 sisyphus+269312.100.1.1 1617990316 installed
<13>Apr 16 11:11:35 rpmi: libglibmm-2.66.0-alt1 sisyphus+265519.100.2.1 1612122114 installed
<13>Apr 16 11:11:35 rpmi: libatkmm-2.28.1-alt1 sisyphus+263407.200.4.1 1608464525 installed
<13>Apr 16 11:11:35 rpmi: gtk-update-icon-cache-3.24.28-alt1 sisyphus+268501.600.4.2 1617043128 installed
<13>Apr 16 11:11:35 rpmi: libdbus-glib-1:0.110-alt1 sisyphus+261272.100.1.1 1604838952 installed
<13>Apr 16 11:11:35 rpmi: gcc-c++-common-1.4.27-alt1 sisyphus+262033.600.7.2 1607340230 installed
<13>Apr 16 11:11:36 rpmi: libstdc++10-devel-10.2.1-alt3 sisyphus+267829.100.1.1 1615808579 installed
<13>Apr 16 11:11:37 rpmi: gcc10-c++-10.2.1-alt3 sisyphus+267829.100.1.1 1615808579 installed
<13>Apr 16 11:11:37 rpmi: libbrotlicommon-1.0.9-alt2 sisyphus+257777.100.1.1 1599688017 installed
<13>Apr 16 11:11:37 rpmi: libbrotlidec-1.0.9-alt2 sisyphus+257777.100.1.1 1599688017 installed
<13>Apr 16 11:11:38 rpmi: libharfbuzz-2.6.8-alt1 sisyphus+254028.100.1.1 1593106819 installed
<13>Apr 16 11:11:38 rpmi: libfreetype-2.10.4-alt2 sisyphus+260293.100.2.1 1604479496 installed
<13>Apr 16 11:11:38 rpmi: fontconfig-2.13.1-alt1 sisyphus+257555.100.1.1 1599475160 installed
Updating fonts cache: <29>Apr 16 11:11:39 fontconfig: Updating fonts cache: succeeded
[ DONE ]
<13>Apr 16 11:11:39 rpmi: libcairo-1:1.16.0-alt1 sisyphus+226534.100.2.3 1554515535 installed
<13>Apr 16 11:11:39 rpmi: libcairomm-1.14.2-alt1 sisyphus+263407.240.4.1 1608464580 installed
<13>Apr 16 11:11:39 rpmi: libXft-2.3.3-alt1 sisyphus+225206.1000.3.2 1552987708 installed
<13>Apr 16 11:11:39 rpmi: libpango-1.48.4-alt1 sisyphus+268501.500.4.2 1617042821 installed
<13>Apr 16 11:11:39 rpmi: libgtk+2-2.24.33-alt1 sisyphus+263711.100.20.1 1609408077 installed
<13>Apr 16 11:11:39 rpmi: libpangomm-2.46.0-alt1 sisyphus+265519.200.2.1 1612122197 installed
<13>Apr 16 11:11:40 rpmi: libgtkmm2-2.24.5-alt1 1475043238 installed
<13>Apr 16 11:11:40 rpmi: libharfbuzz-icu-2.6.8-alt1 sisyphus+254028.100.1.1 1593106819 installed
<13>Apr 16 11:11:40 rpmi: libharfbuzz-gobject-2.6.8-alt1 sisyphus+254028.100.1.1 1593106819 installed
<13>Apr 16 11:11:40 rpmi: libgdbm-1.8.3-alt10 1454943334 installed
<13>Apr 16 11:11:40 rpmi: xml-utils-1:2.9.10-alt6 sisyphus+265234.30740.49.1 1613765060 installed
<13>Apr 16 11:11:40 rpmi: rpm-build-gir-0.7.3-alt3 sisyphus+242150.100.1.1 1575312005 installed
<13>Apr 16 11:11:40 rpmi: rpm-macros-alternatives-0.5.1-alt1 sisyphus+226946.100.1.1 1554830426 installed
<13>Apr 16 11:11:40 rpmi: alternatives-0.5.1-alt1 sisyphus+226946.100.1.1 1554830426 installed
<13>Apr 16 11:11:40 rpmi: ca-certificates-2021.03.24-alt1 sisyphus+268304.300.1.1 1616591829 installed
<13>Apr 16 11:11:40 rpmi: ca-trust-0.1.2-alt1 sisyphus+233348.100.1.1 1561653823 installed
<13>Apr 16 11:11:40 rpmi: p11-kit-trust-0.23.15-alt2 sisyphus+252784.100.2.2 1591274901 installed
<13>Apr 16 11:11:40 rpmi: libcrypto1.1-1.1.1k-alt1 sisyphus+268375.100.1.1 1616684255 installed
<13>Apr 16 11:11:40 rpmi: libssl1.1-1.1.1k-alt1 sisyphus+268375.100.1.1 1616684255 installed
<13>Apr 16 11:11:40 rpmi: libpython3-3.9.4-alt1 sisyphus+268966.100.1.1 1617609166 installed
<13>Apr 16 11:11:40 rpmi: python3-3.9.4-alt1 sisyphus+268966.100.1.1 1617609166 installed
<13>Apr 16 11:11:42 rpmi: python3-base-3.9.4-alt1 sisyphus+268966.100.1.1 1617609166 installed
<13>Apr 16 11:11:42 rpmi: glib2-devel-2.68.1-alt1 sisyphus+269248.100.1.1 1617921065 installed
<13>Apr 16 11:11:42 rpmi: libgio-devel-2.68.1-alt1 sisyphus+269248.100.1.1 1617921065 installed
<13>Apr 16 11:11:42 rpmi: libglibmm-devel-2.66.0-alt1 sisyphus+265519.100.2.1 1612122114 installed
<13>Apr 16 11:11:43 rpmi: libfreetype-devel-2.10.4-alt2 sisyphus+260293.100.2.1 1604479496 installed
<13>Apr 16 11:11:43 rpmi: libharfbuzz-devel-2.6.8-alt1 sisyphus+254028.100.1.1 1593106819 installed
<13>Apr 16 11:11:43 rpmi: fontconfig-devel-2.13.1-alt1 sisyphus+257555.100.1.1 1599475160 installed
<13>Apr 16 11:11:43 rpmi: libcairo-devel-1:1.16.0-alt1 sisyphus+226534.100.2.3 1554515535 installed
<13>Apr 16 11:11:43 rpmi: libatk-devel-2.36.0-alt1 sisyphus+249208.100.1.1 1585840406 installed
<13>Apr 16 11:11:43 rpmi: libatkmm-devel-2.28.1-alt1 sisyphus+263407.200.4.1 1608464525 installed
<13>Apr 16 11:11:43 rpmi: libcairomm-devel-1.14.2-alt1 sisyphus+263407.240.4.1 1608464580 installed
<13>Apr 16 11:11:43 rpmi: libXft-devel-2.3.3-alt1 sisyphus+225206.1000.3.2 1552987708 installed
<13>Apr 16 11:11:43 rpmi: libpango-devel-1.48.4-alt1 sisyphus+268501.500.4.2 1617042821 installed
<13>Apr 16 11:11:43 rpmi: libpangomm-devel-2.46.0-alt1 sisyphus+265519.200.2.1 1612122197 installed
<13>Apr 16 11:11:43 rpmi: libgdk-pixbuf-devel-2.42.6-alt1 sisyphus+269312.100.1.1 1617990316 installed
<13>Apr 16 11:11:43 rpmi: gtk-builder-convert-2.24.33-alt1 sisyphus+263711.100.20.1 1609407991 installed
<13>Apr 16 11:11:43 rpmi: libgtk+2-devel-2.24.33-alt1 sisyphus+263711.100.20.1 1609408077 installed
<86>Apr 16 11:11:43 groupadd[1476919]: group added to /etc/group: name=_keytab, GID=499
<86>Apr 16 11:11:43 groupadd[1476919]: group added to /etc/gshadow: name=_keytab
<86>Apr 16 11:11:43 groupadd[1476919]: new group: name=_keytab, GID=499
<13>Apr 16 11:11:43 rpmi: libkrb5-1.19.1-alt2 sisyphus+267847.100.1.1 1615814853 installed
<86>Apr 16 11:11:43 groupadd[1477316]: group added to /etc/group: name=sasl, GID=498
<86>Apr 16 11:11:43 groupadd[1477316]: group added to /etc/gshadow: name=sasl
<86>Apr 16 11:11:43 groupadd[1477316]: new group: name=sasl, GID=498
<13>Apr 16 11:11:43 rpmi: libsasl2-3-2.1.27-alt2.1 sisyphus+255909.100.2.1 1597199456 installed
<13>Apr 16 11:11:43 rpmi: libldap-2.4.57-alt1 sisyphus+266287.100.1.1 1613244306 installed
<13>Apr 16 11:11:43 rpmi: libGConf-3.2.6-alt4 sisyphus+248231.100.1.1 1584821804 installed
<13>Apr 16 11:11:43 rpmi: libGConf-devel-3.2.6-alt4 sisyphus+248231.100.1.1 1584821804 installed
<13>Apr 16 11:11:43 rpmi: libgtkmm2-devel-2.24.5-alt1 1475043238 installed
<13>Apr 16 11:11:43 rpmi: mm-common-1.0.2-alt1 sisyphus+258745.100.1.1 1601186592 installed
<13>Apr 16 11:11:43 rpmi: gcc-c++-10-alt1 sisyphus+263054.200.3.1 1607516810 installed
<13>Apr 16 11:11:44 rpmi: doxygen-1:1.8.17-alt2 sisyphus+251932.100.4.1 1589893423 installed
Building target platforms: i586
Building for target i586
Wrote: /usr/src/in/nosrpm/libgconfmm2-2.28.3-alt1.nosrc.rpm (w1.gzdio)
Installing libgconfmm2-2.28.3-alt1.src.rpm
Building target platforms: i586
Building for target i586
Executing(%prep): /bin/sh -e /usr/src/tmp/rpm-tmp.9983
+ umask 022
+ /bin/mkdir -p /usr/src/RPM/BUILD
+ cd /usr/src/RPM/BUILD
+ cd /usr/src/RPM/BUILD
+ rm -rf gconfmm-2.28.3
+ echo 'Source #0 (gconfmm-2.28.3.tar.bz2):'
Source #0 (gconfmm-2.28.3.tar.bz2):
+ /bin/tar -xf -
+ /bin/bzip2 -dc /usr/src/RPM/SOURCES/gconfmm-2.28.3.tar.bz2
+ cd gconfmm-2.28.3
+ /bin/chmod -c -Rf u+rwX,go-w .
+ echo 'Patch #0 (gconfmm-2.28.3-cxx11.patch):'
Patch #0 (gconfmm-2.28.3-cxx11.patch):
+ /usr/bin/patch -p0
patching file configure.ac
+ exit 0
Executing(%build): /bin/sh -e /usr/src/tmp/rpm-tmp.9983
+ umask 022
+ /bin/mkdir -p /usr/src/RPM/BUILD
+ cd /usr/src/RPM/BUILD
+ cd gconfmm-2.28.3
+ mm-common-prepare
mm-common-prepare: putting auxiliary files in './build'.
mm-common-prepare: symlinking file 'dist-changelog.am'
mm-common-prepare: putting documentation utilities in './docs'.
mm-common-prepare: symlinking file 'doxygen-extra.css'
+ autoreconf -fisv
autoreconf-default: Entering directory `.'
autoreconf-default: configure.ac: not using Gettext
autoreconf-default: running: aclocal --force -I build ${ACLOCAL_FLAGS}
autoreconf-default: configure.ac: tracing
autoreconf-default: running: libtoolize --force --install
libtoolize-default: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build'.
libtoolize-default: linking file 'build/config.guess'
libtoolize-default: linking file 'build/config.sub'
libtoolize-default: linking file 'build/install-sh'
libtoolize-default: linking file 'build/ltmain.sh'
libtoolize-default: putting macros in AC_CONFIG_MACRO_DIRS, 'build'.
libtoolize-default: linking file 'build/libtool.m4'
libtoolize-default: linking file 'build/ltoptions.m4'
libtoolize-default: linking file 'build/ltsugar.m4'
libtoolize-default: linking file 'build/ltversion.m4'
libtoolize-default: linking file 'build/lt~obsolete.m4'
autoreconf-default: configure.ac: not using Intltool
autoreconf-default: configure.ac: not using gtk-doc
autoreconf-default: running: /usr/bin/autoconf-2.60 --force
autoreconf-default: running: /usr/bin/autoheader-2.60 --force
autoreconf-default: running: automake --add-missing --force-missing
configure.ac:48: installing 'build/compile'
configure.ac:28: installing 'build/missing'
gconf/gconfmm/Makefile.am: installing 'build/depcomp'
autoreconf-default: Leaving directory `.'
+ CFLAGS='-pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic'
+ export CFLAGS
+ CXXFLAGS='-pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic'
+ export CXXFLAGS
+ FFLAGS='-pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic'
+ export FFLAGS
+ FCFLAGS='-pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic'
+ export FCFLAGS
+ '[' -n '' ']'
++ sed -r 's/(^|[[:space:]]+)-[^m][^[:space:]]*//g'
++ printf %s '-pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic'
+ ASFLAGS=' -march=i586 -mtune=generic'
+ export ASFLAGS
+ export lt_cv_deplibs_check_method=pass_all
+ lt_cv_deplibs_check_method=pass_all
+ readlink -e -- ./configure
+ xargs -ri dirname -- '{}'
+ xargs -ri find '{}' -type f '(' -name config.sub -or -name config.guess ')' -printf '%h/\n'
+ sort -u
+ xargs -rn1 install -pm755 -- /usr/share/gnu-config/config.sub /usr/share/gnu-config/config.guess
+ ./configure --build=i586-alt-linux --host=i586-alt-linux --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib --libexecdir=/usr/lib --localstatedir=/var/lib --sharedstatedir=/var/lib --mandir=/usr/share/man --infodir=/usr/share/info --disable-dependency-tracking --disable-silent-rules --without-included-gettext --disable-static --enable-shared
configure: WARNING: unrecognized options: --without-included-gettext
checking for a BSD-compatible install... /bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking whether UID '706' is supported by ustar format... yes
checking whether GID '706' is supported by ustar format... yes
checking how to create a ustar tar archive... gnutar
checking whether make supports nested variables... (cached) yes
checking whether to enable maintainer-specific portions of Makefiles... no
checking whether make supports GNU make features... yes
checking for i586-alt-linux-g++... i586-alt-linux-g++
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether i586-alt-linux-g++ accepts -g... yes
checking whether make supports the include directive... yes (GNU style)
checking dependency style of i586-alt-linux-g++... none
checking whether i586-alt-linux-g++ supports C++11 features by default... yes
checking build system type... i586-alt-linux-gnu
checking host system type... i586-alt-linux-gnu
checking how to print strings... printf
checking for i586-alt-linux-gcc... i586-alt-linux-gcc
checking whether we are using the GNU C compiler... yes
checking whether i586-alt-linux-gcc accepts -g... yes
checking for i586-alt-linux-gcc option to accept ISO C89... none needed
checking whether i586-alt-linux-gcc understands -c and -o together... yes
checking dependency style of i586-alt-linux-gcc... none
checking for a sed that does not truncate output... /bin/sed
checking for grep that handles long lines and -e... /bin/grep
checking for egrep... /bin/grep -E
checking for fgrep... /bin/grep -F
checking for ld used by i586-alt-linux-gcc... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B
checking the name lister (/usr/bin/nm -B) interface... BSD nm
checking whether ln -s works... yes
checking the maximum length of command line arguments... 1572864
checking how to convert i586-alt-linux-gnu file names to i586-alt-linux-gnu format... func_convert_file_noop
checking how to convert i586-alt-linux-gnu file names to toolchain format... func_convert_file_noop
checking for /usr/bin/ld option to reload object files... -r
checking for i586-alt-linux-objdump... objdump
checking how to recognize dependent libraries... (cached) pass_all
checking for i586-alt-linux-dlltool... dlltool
checking how to associate runtime and link libraries... printf %s\n
checking for i586-alt-linux-ar... no
checking for ar... ar
checking for archiver @FILE support... @
checking for i586-alt-linux-strip... no
checking for strip... strip
checking for i586-alt-linux-ranlib... no
checking for ranlib... ranlib
checking command to parse /usr/bin/nm -B output from i586-alt-linux-gcc object... ok
checking for sysroot... no
checking for a working dd... /bin/dd
checking how to truncate binary pipes... /bin/dd bs=4096 count=1
checking for i586-alt-linux-mt... no
checking for mt... no
checking if : is a manifest tool... no
checking how to run the C preprocessor... i586-alt-linux-gcc -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if i586-alt-linux-gcc supports -fno-rtti -fno-exceptions... no
checking for i586-alt-linux-gcc option to produce PIC... -fPIC -DPIC
checking if i586-alt-linux-gcc PIC flag -fPIC -DPIC works... yes
checking if i586-alt-linux-gcc static flag -static works... no
checking if i586-alt-linux-gcc supports -c -o file.o... yes
checking if i586-alt-linux-gcc supports -c -o file.o... (cached) yes
checking whether the i586-alt-linux-gcc linker (/usr/bin/ld) supports shared libraries... yes
checking whether -lc should be explicitly linked in... no
checking dynamic linker characteristics... GNU/Linux ld.so
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... no
checking how to run the C++ preprocessor... i586-alt-linux-g++ -E
checking for ld used by i586-alt-linux-g++... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking whether the i586-alt-linux-g++ linker (/usr/bin/ld) supports shared libraries... yes
checking for i586-alt-linux-g++ option to produce PIC... -fPIC -DPIC
checking if i586-alt-linux-g++ PIC flag -fPIC -DPIC works... yes
checking if i586-alt-linux-g++ static flag -static works... no
checking if i586-alt-linux-g++ supports -c -o file.o... yes
checking if i586-alt-linux-g++ supports -c -o file.o... (cached) yes
checking whether the i586-alt-linux-g++ linker (/usr/bin/ld) supports shared libraries... yes
checking dynamic linker characteristics... (cached) GNU/Linux ld.so
checking how to hardcode library paths into programs... immediate
checking for i586-alt-linux-pkg-config... no
checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for glibmm-2.4 >= 2.14.1 gconf-2.0 >= 2.4.0... yes
checking for GTHREAD_CFLAGS... -pthread
checking for GMMPROC_DIR... /usr/lib/glibmm-2.4/proc
configure: Deprecated API will be built, for backwards-compatibility.
checking for perl... /usr/bin/perl
checking for dot... dot
checking for doxygen... /usr/bin/doxygen
checking for xsltproc... xsltproc
checking for libstdc documentation... /usr/share/mm-common/doctags/libstdc++.tag@http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen
checking for libsigc documentation... /usr/share/doc/libsigc++-2.0/reference/libsigc++-2.0.tag@file:///usr/share/doc/libsigc++-2.0/reference/html
checking for glibmm documentation... /usr/share/doc/glibmm-2.4/reference/glibmm-2.4.tag@file:///usr/share/doc/glibmm-2.4/reference/html
checking for cairomm documentation... /usr/share/doc/cairomm-1.0/reference/cairomm-1.0.tag@file:///usr/share/doc/cairomm-1.0/reference/html
checking which C++ compiler warning flags to use... -Wall
checking that generated files are newer than configure... done
configure: creating ./config.status
config.status: creating Makefile
config.status: creating tools/Makefile
config.status: creating gconf/gconfmm-2.6.pc
config.status: creating gconf/gconfmm-2.6-uninstalled.pc
config.status: creating gconf/src/Makefile
config.status: creating gconf/gconfmm/Makefile
config.status: creating docs/Makefile
config.status: creating docs/reference/Doxyfile
config.status: creating config.h
config.status: creating gconf/gconfmmconfig.h
config.status: executing depfiles commands
config.status: executing libtool commands
configure: WARNING: unrecognized options: --without-included-gettext
+ make -j8
make  all-recursive
Making all in gconf/gconfmm
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o init.lo init.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c init.cc  -fPIC -DPIC -o .libs/init.o
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o schema.lo schema.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c schema.cc  -fPIC -DPIC -o .libs/schema.o
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from ../gconfmm/schema.h:36,
                 from schema.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/schema.h:7,
                 from schema.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from ../gconfmm/schema.h:36,
                 from schema.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/schema.h:7,
                 from schema.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from ../gconfmm/schema.h:36,
                 from schema.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/schema.h:7,
                 from schema.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o changeset.lo changeset.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c changeset.cc  -fPIC -DPIC -o .libs/changeset.o
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-changeset.h:23,
                 from changeset.cc:29:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/changeset.h:7,
                 from changeset.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-changeset.h:23,
                 from changeset.cc:29:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/changeset.h:7,
                 from changeset.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-changeset.h:23,
                 from changeset.cc:29:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/changeset.h:7,
                 from changeset.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o value.lo value.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c value.cc  -fPIC -DPIC -o .libs/value.o
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from value.cc:29:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/value.h:7,
                 from value.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from value.cc:29:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/value.h:7,
                 from value.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from value.cc:29:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/value.h:7,
                 from value.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o wrap_init.lo wrap_init.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c wrap_init.cc  -fPIC -DPIC -o .libs/wrap_init.o
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from client.h:31,
                 from wrap_init.cc:16:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from wrap_init.cc:2:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from client.h:31,
                 from wrap_init.cc:16:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from wrap_init.cc:2:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from client.h:31,
                 from wrap_init.cc:16:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from wrap_init.cc:2:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o entry.lo entry.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c entry.cc  -fPIC -DPIC -o .libs/entry.o
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from ../gconfmm/schema.h:36,
                 from ../gconfmm/entry.h:32,
                 from entry.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/entry.h:7,
                 from entry.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from ../gconfmm/schema.h:36,
                 from ../gconfmm/entry.h:32,
                 from entry.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/entry.h:7,
                 from entry.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from ../gconfmm/schema.h:36,
                 from ../gconfmm/entry.h:32,
                 from entry.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/entry.h:7,
                 from entry.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o setinterface.lo setinterface.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c setinterface.cc  -fPIC -DPIC -o .libs/setinterface.o
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o callback.lo callback.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c callback.cc  -fPIC -DPIC -o .libs/callback.o
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:56:3: error: template with C linkage
   56 |   template<typename _Tp, _Tp __v>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:71:3: error: template with C linkage
   71 |   template<typename _Tp, _Tp __v>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:80:3: error: template with C linkage
   80 |   template<bool __v>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:91:3: error: template with C linkage
   91 |   template<bool, typename, typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:94:3: error: template with C linkage
   94 |   template <typename _Type>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:98:3: error: template with C linkage
   98 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:101:3: error: template with C linkage
  101 |   template<typename...>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:104:3: error: template specialization with C linkage
  104 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:109:3: error: template with C linkage
  109 |   template<typename _B1>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:114:3: error: template with C linkage
  114 |   template<typename _B1, typename _B2>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:119:3: error: template with C linkage
  119 |   template<typename _B1, typename _B2, typename _B3, typename... _Bn>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:124:3: error: template with C linkage
  124 |   template<typename...>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:127:3: error: template specialization with C linkage
  127 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:132:3: error: template with C linkage
  132 |   template<typename _B1>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:137:3: error: template with C linkage
  137 |   template<typename _B1, typename _B2>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:142:3: error: template with C linkage
  142 |   template<typename _B1, typename _B2, typename _B3, typename... _Bn>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:147:3: error: template with C linkage
  147 |   template<typename _Pp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:188:3: error: template with C linkage
  188 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:190:3: error: template with C linkage
  190 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:192:3: error: template with C linkage
  192 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:194:3: error: template with C linkage
  194 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:200:3: error: template with C linkage
  200 |   template <typename _Tp, size_t = sizeof(_Tp)>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:204:3: error: template with C linkage
  204 |   template <typename _TypeIdentity,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:219:3: error: template with C linkage
  219 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:226:3: error: template with C linkage
  226 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:230:3: error: template with C linkage
  230 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:233:3: error: template with C linkage
  233 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:238:3: error: template with C linkage
  238 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:242:3: error: template specialization with C linkage
  242 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:247:3: error: template with C linkage
  247 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:252:3: error: template with C linkage
  252 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:256:3: error: template specialization with C linkage
  256 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:260:3: error: template specialization with C linkage
  260 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:264:3: error: template specialization with C linkage
  264 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:268:3: error: template specialization with C linkage
  268 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:273:3: error: template specialization with C linkage
  273 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:284:3: error: template specialization with C linkage
  284 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:288:3: error: template specialization with C linkage
  288 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:292:3: error: template specialization with C linkage
  292 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:296:3: error: template specialization with C linkage
  296 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:300:3: error: template specialization with C linkage
  300 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:304:3: error: template specialization with C linkage
  304 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:308:3: error: template specialization with C linkage
  308 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:312:3: error: template specialization with C linkage
  312 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:316:3: error: template specialization with C linkage
  316 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:320:3: error: template specialization with C linkage
  320 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:364:3: error: template with C linkage
  364 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:369:3: error: template with C linkage
  369 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:373:3: error: template specialization with C linkage
  373 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:377:3: error: template specialization with C linkage
  377 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:381:3: error: template specialization with C linkage
  381 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:386:3: error: template specialization with C linkage
  386 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:392:3: error: template with C linkage
  392 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:398:3: error: template with C linkage
  398 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:402:3: error: template with C linkage
  402 |   template<typename _Tp, std::size_t _Size>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:406:3: error: template with C linkage
  406 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:410:3: error: template with C linkage
  410 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:414:3: error: template with C linkage
  414 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:419:3: error: template with C linkage
  419 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:425:3: error: template with C linkage
  425 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:429:3: error: template with C linkage
  429 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:434:3: error: template with C linkage
  434 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:438:3: error: template with C linkage
  438 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:442:3: error: template with C linkage
  442 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:446:3: error: template with C linkage
  446 |   template<typename _Tp, typename _Cp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:451:3: error: template with C linkage
  451 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:456:3: error: template with C linkage
  456 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:460:3: error: template with C linkage
  460 |   template<typename _Tp, typename _Cp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:465:3: error: template with C linkage
  465 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:471:3: error: template with C linkage
  471 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:477:3: error: template with C linkage
  477 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:483:3: error: template with C linkage
  483 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:489:3: error: template with C linkage
  489 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:493:3: error: template with C linkage
  493 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:497:3: error: template with C linkage
  497 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:503:3: error: template with C linkage
  503 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:507:3: error: template specialization with C linkage
  507 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:512:3: error: template with C linkage
  512 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:518:3: error: template with C linkage
  518 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:526:3: error: template with C linkage
  526 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:533:3: error: template with C linkage
  533 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:539:3: error: template with C linkage
  539 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:546:3: error: template with C linkage
  546 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:552:3: error: template with C linkage
  552 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:556:3: error: template with C linkage
  556 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:563:3: error: template with C linkage
  563 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:567:3: error: template with C linkage
  567 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:571:3: error: template with C linkage
  571 |   template<typename _Tp, typename _Cp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:576:3: error: template with C linkage
  576 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:581:3: error: template with C linkage
  581 |   template<typename, typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:584:3: error: template with C linkage
  584 |   template<typename _Tp, typename... _Types>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:588:3: error: template with C linkage
  588 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:607:3: error: template with C linkage
  607 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:626:3: error: template with C linkage
  626 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:631:3: error: template with C linkage
  631 |   template<typename...> using __void_t = void;
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:635:3: error: template with C linkage
  635 |   template<typename _Tp, typename = void>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:640:3: error: template with C linkage
  640 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:648:3: error: template with C linkage
  648 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:652:3: error: template with C linkage
  652 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:657:3: error: template with C linkage
  657 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:661:3: error: template with C linkage
  661 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:666:3: error: template with C linkage
  666 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:675:3: error: template with C linkage
  675 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:684:3: error: template with C linkage
  684 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:694:3: error: template with C linkage
  694 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:705:3: error: template with C linkage
  705 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:714:3: error: template with C linkage
  714 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:720:3: error: template with C linkage
  720 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:728:3: error: template with C linkage
  728 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:735:3: error: template with C linkage
  735 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:740:3: error: template with C linkage
  740 |   template<typename _Tp,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:745:3: error: template with C linkage
  745 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:751:3: error: template with C linkage
  751 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:757:3: error: template with C linkage
  757 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:770:3: error: template with C linkage
  770 |   template<typename _Tp, typename _Up = _Tp&&>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:774:3: error: template with C linkage
  774 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:778:3: error: template with C linkage
  778 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:781:3: error: template with C linkage
  781 |   template<typename, unsigned = 0>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:784:3: error: template with C linkage
  784 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:787:3: error: template with C linkage
  787 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:792:3: error: template with C linkage
  792 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:804:5: error: template with C linkage
  804 |     template<typename _Tp, typename = decltype(declval<_Tp&>().~_Tp())>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:807:5: error: template with C linkage
  807 |     template<typename>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:811:3: error: template with C linkage
  811 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:818:3: error: template with C linkage
  818 |   template<typename _Tp,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:825:3: error: template with C linkage
  825 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:831:3: error: template with C linkage
  831 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:835:3: error: template with C linkage
  835 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:840:3: error: template with C linkage
  840 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:854:5: error: template with C linkage
  854 |     template<typename _Tp>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:858:5: error: template with C linkage
  858 |     template<typename>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:862:3: error: template with C linkage
  862 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:869:3: error: template with C linkage
  869 |   template<typename _Tp,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:876:3: error: template with C linkage
  876 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:882:3: error: template with C linkage
  882 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:886:3: error: template with C linkage
  886 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:891:3: error: template with C linkage
  891 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:899:3: error: template with C linkage
  899 |   template<typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:905:3: error: template with C linkage
  905 |   template<typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:914:3: error: template with C linkage
  914 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:922:3: error: template with C linkage
  922 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:925:3: error: template with C linkage
  925 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:929:3: error: template with C linkage
  929 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:935:3: error: template with C linkage
  935 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:943:3: error: template with C linkage
  943 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:946:3: error: template with C linkage
  946 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:950:3: error: template with C linkage
  950 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:956:3: error: template with C linkage
  956 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:964:3: error: template with C linkage
  964 |   template<bool, typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:969:3: error: template with C linkage
  969 |   template<typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:974:3: error: template with C linkage
  974 |   template<typename _Tp, typename _Arg>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:979:3: error: template with C linkage
  979 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:984:3: error: template with C linkage
  984 |   template<typename _Tp, size_t _Num>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1001:3: error: template with C linkage
 1001 |   template<typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1007:3: error: template with C linkage
 1007 |   template<typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1016:3: error: template with C linkage
 1016 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1025:3: error: template with C linkage
 1025 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1028:3: error: template with C linkage
 1028 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1032:3: error: template with C linkage
 1032 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1038:3: error: template with C linkage
 1038 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1046:3: error: template with C linkage
 1046 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1049:3: error: template with C linkage
 1049 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1053:3: error: template with C linkage
 1053 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1059:3: error: template with C linkage
 1059 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1068:3: error: template with C linkage
 1068 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1076:3: error: template with C linkage
 1076 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1079:3: error: template with C linkage
 1079 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1083:3: error: template with C linkage
 1083 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1089:3: error: template with C linkage
 1089 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1097:3: error: template with C linkage
 1097 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1100:3: error: template with C linkage
 1100 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1104:3: error: template with C linkage
 1104 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1110:3: error: template with C linkage
 1110 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1118:3: error: template with C linkage
 1118 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1123:3: error: template with C linkage
 1123 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1130:3: error: template with C linkage
 1130 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1138:3: error: template with C linkage
 1138 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1141:3: error: template with C linkage
 1141 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1145:3: error: template with C linkage
 1145 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1151:3: error: template with C linkage
 1151 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1159:3: error: template with C linkage
 1159 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1162:3: error: template with C linkage
 1162 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1166:3: error: template with C linkage
 1166 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1172:3: error: template with C linkage
 1172 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1181:3: error: template with C linkage
 1181 |   template<typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1190:3: error: template with C linkage
 1190 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1200:5: error: template with C linkage
 1200 |     template <typename _Tp>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1203:5: error: template with C linkage
 1203 |     template <typename _Tp>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1210:3: error: template with C linkage
 1210 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1217:3: error: template with C linkage
 1217 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1222:3: error: template with C linkage
 1222 |   template <typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1228:3: error: template with C linkage
 1228 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1231:3: error: template with C linkage
 1231 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1235:3: error: template with C linkage
 1235 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1243:3: error: template with C linkage
 1243 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1251:3: error: template with C linkage
 1251 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1254:3: error: template with C linkage
 1254 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1258:3: error: template with C linkage
 1258 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1266:3: error: template with C linkage
 1266 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1275:3: error: template with C linkage
 1275 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1283:3: error: template with C linkage
 1283 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1286:3: error: template with C linkage
 1286 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1290:3: error: template with C linkage
 1290 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1296:3: error: template with C linkage
 1296 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1304:3: error: template with C linkage
 1304 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1307:3: error: template with C linkage
 1307 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1311:3: error: template with C linkage
 1311 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1317:3: error: template with C linkage
 1317 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1326:3: error: template with C linkage
 1326 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1337:3: error: template with C linkage
 1337 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1349:3: error: template with C linkage
 1349 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1358:3: error: template with C linkage
 1358 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1362:3: error: template with C linkage
 1362 |   template<typename _Tp, std::size_t _Size>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1366:3: error: template with C linkage
 1366 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1371:3: error: template with C linkage
 1371 |   template<typename, unsigned _Uint>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1375:3: error: template with C linkage
 1375 |   template<typename _Tp, unsigned _Uint, std::size_t _Size>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1382:3: error: template with C linkage
 1382 |   template<typename _Tp, unsigned _Uint>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1393:3: error: template with C linkage
 1393 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1410:3: error: template with C linkage
 1410 |   template<typename _Base, typename _Derived>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1415:3: error: template with C linkage
 1415 |   template<typename _From, typename _To,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1425:3: error: template with C linkage
 1425 |   template<typename _From, typename _To>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1446:3: error: template with C linkage
 1446 |   template<typename _From, typename _To>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1452:3: error: template with C linkage
 1452 |   template<typename _ToElementType, typename _FromElementType>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1456:3: error: template with C linkage
 1456 |   template<typename _From, typename _To,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1465:3: error: template with C linkage
 1465 |   template<typename _From, typename _To>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1486:3: error: template with C linkage
 1486 |   template<typename _From, typename _To>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1508:3: error: template with C linkage
 1508 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1512:3: error: template with C linkage
 1512 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1517:3: error: template with C linkage
 1517 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1521:3: error: template with C linkage
 1521 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1526:3: error: template with C linkage
 1526 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1530:3: error: template with C linkage
 1530 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1534:3: error: template with C linkage
 1534 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1538:3: error: template with C linkage
 1538 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1543:3: error: template with C linkage
 1543 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1548:3: error: template with C linkage
 1548 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1553:3: error: template with C linkage
 1553 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1565:3: error: template with C linkage
 1565 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1569:3: error: template with C linkage
 1569 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1573:3: error: template with C linkage
 1573 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1577:3: error: template with C linkage
 1577 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1581:3: error: template with C linkage
 1581 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1585:3: error: template with C linkage
 1585 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1592:3: error: template with C linkage
 1592 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1596:3: error: template with C linkage
 1596 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1600:3: error: template with C linkage
 1600 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1604:3: error: template with C linkage
 1604 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1608:3: error: template with C linkage
 1608 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1613:3: error: template with C linkage
 1613 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1618:3: error: template with C linkage
 1618 |   template<typename _Tp, bool = __is_referenceable<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1622:3: error: template with C linkage
 1622 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1627:3: error: template with C linkage
 1627 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1634:3: error: template with C linkage
 1634 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1638:3: error: template with C linkage
 1638 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1642:3: error: template with C linkage
 1642 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1649:3: error: template with C linkage
 1649 |   template<typename _Unqualified, bool _IsConst, bool _IsVol>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1652:3: error: template with C linkage
 1652 |   template<typename _Unqualified>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1656:3: error: template with C linkage
 1656 |   template<typename _Unqualified>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1660:3: error: template with C linkage
 1660 |   template<typename _Unqualified>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1664:3: error: template with C linkage
 1664 |   template<typename _Unqualified>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1668:3: error: template with C linkage
 1668 |   template<typename _Qualified, typename _Unqualified,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1680:3: error: template with C linkage
 1680 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1684:3: error: template specialization with C linkage
 1684 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1688:3: error: template specialization with C linkage
 1688 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1692:3: error: template specialization with C linkage
 1692 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1696:3: error: template specialization with C linkage
 1696 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1700:3: error: template specialization with C linkage
 1700 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1704:3: error: template specialization with C linkage
 1704 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1730:3: error: template with C linkage
 1730 |   template<typename _Tp,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1735:3: error: template with C linkage
 1735 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1749:5: error: template with C linkage
 1749 |     template<typename...> struct _List { };
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1751:5: error: template with C linkage
 1751 |     template<typename _Tp, typename... _Up>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1755:5: error: template with C linkage
 1755 |     template<size_t _Sz, typename _Tp, bool = (_Sz <= _Tp::__size)>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1758:5: error: template with C linkage
 1758 |     template<size_t _Sz, typename _Uint, typename... _UInts>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1762:5: error: template with C linkage
 1762 |     template<size_t _Sz, typename _Uint, typename... _UInts>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1769:3: error: template with C linkage
 1769 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1789:3: error: template specialization with C linkage
 1789 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1806:3: error: template specialization with C linkage
 1806 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1813:3: error: template specialization with C linkage
 1813 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1824:3: error: template with C linkage
 1824 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1829:3: error: template specialization with C linkage
 1829 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1834:3: error: template with C linkage
 1834 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1838:3: error: template specialization with C linkage
 1838 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1842:3: error: template specialization with C linkage
 1842 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1846:3: error: template specialization with C linkage
 1846 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1850:3: error: template specialization with C linkage
 1850 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1854:3: error: template specialization with C linkage
 1854 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1858:3: error: template specialization with C linkage
 1858 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1884:3: error: template with C linkage
 1884 |   template<typename _Tp,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1889:3: error: template with C linkage
 1889 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1901:3: error: template with C linkage
 1901 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1915:3: error: template specialization with C linkage
 1915 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1932:3: error: template specialization with C linkage
 1932 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1939:3: error: template specialization with C linkage
 1939 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1950:3: error: template with C linkage
 1950 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1955:3: error: template specialization with C linkage
 1955 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1960:3: error: template with C linkage
 1960 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1964:3: error: template with C linkage
 1964 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1971:3: error: template with C linkage
 1971 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1975:3: error: template with C linkage
 1975 |   template<typename _Tp, std::size_t _Size>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1979:3: error: template with C linkage
 1979 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1984:3: error: template with C linkage
 1984 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1988:3: error: template with C linkage
 1988 |   template<typename _Tp, std::size_t _Size>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1992:3: error: template with C linkage
 1992 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:1998:3: error: template with C linkage
 1998 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2002:3: error: template with C linkage
 2002 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2008:3: error: template with C linkage
 2008 |   template<typename _Tp, typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2012:3: error: template with C linkage
 2012 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2017:3: error: template with C linkage
 2017 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2023:3: error: template with C linkage
 2023 |   template<typename _Tp, bool = __or_<__is_referenceable<_Tp>,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2028:3: error: template with C linkage
 2028 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2032:3: error: template with C linkage
 2032 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2039:3: error: template with C linkage
 2039 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2043:3: error: template with C linkage
 2043 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2047:3: error: template with C linkage
 2047 |   template<std::size_t _Len>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2067:3: error: template with C linkage
 2067 |   template<std::size_t _Len, std::size_t _Align =
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2078:3: error: template with C linkage
 2078 |   template <typename... _Types>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2085:3: error: template with C linkage
 2085 |   template <typename _Tp, typename... _Types>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2106:3: error: template with C linkage
 2106 |   template <size_t _Len, typename... _Types>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2122:3: error: template with C linkage
 2122 |   template <size_t _Len, typename... _Types>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2127:3: error: template with C linkage
 2127 |   template<typename _Up,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2133:3: error: template with C linkage
 2133 |   template<typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2137:3: error: template with C linkage
 2137 |   template<typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2141:3: error: template with C linkage
 2141 |   template<typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2146:3: error: template with C linkage
 2146 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2156:3: error: template with C linkage
 2156 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2159:3: error: template with C linkage
 2159 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2163:3: error: template with C linkage
 2163 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2169:3: error: template with C linkage
 2169 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2175:3: error: template with C linkage
 2175 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2181:3: error: template with C linkage
 2181 |   template<bool, typename _Tp = void>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2186:3: error: template with C linkage
 2186 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2191:3: error: template with C linkage
 2191 |   template<bool _Cond, typename _Tp = void>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2194:3: error: template with C linkage
 2194 |   template<typename... _Cond>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2199:3: error: template with C linkage
 2199 |   template<bool _Cond, typename _Iftrue, typename _Iffalse>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2204:3: error: template with C linkage
 2204 |   template<typename _Iftrue, typename _Iffalse>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2209:3: error: template with C linkage
 2209 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2214:3: error: template with C linkage
 2214 |   template<typename... _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2221:5: error: template with C linkage
 2221 |     template<typename _Tp, typename _Up>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2227:5: error: template with C linkage
 2227 |     template<typename _Tp, typename _Up>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2239:5: error: template with C linkage
 2239 |     template<typename, typename>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2243:5: error: template with C linkage
 2243 |     template<typename _Tp, typename _Up>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2249:3: error: template specialization with C linkage
 2249 |   template<>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2254:3: error: template with C linkage
 2254 |   template<typename _Tp0>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2260:3: error: template with C linkage
 2260 |   template<typename _Tp1, typename _Tp2,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2269:3: error: template with C linkage
 2269 |   template<typename _Tp1, typename _Tp2>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2279:3: error: template with C linkage
 2279 |   template<typename _Tp1, typename _Tp2>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2284:3: error: template with C linkage
 2284 |   template<typename...>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2288:3: error: template with C linkage
 2288 |   template<typename, typename, typename = void>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2292:3: error: template with C linkage
 2292 |   template<typename _Tp1, typename _Tp2, typename... _Rp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2301:3: error: template with C linkage
 2301 |   template<typename _CTp, typename... _Rp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2308:3: error: template with C linkage
 2308 |   template<typename _CTp, typename _Rp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2312:3: error: template with C linkage
 2312 |   template<typename _Tp, bool = is_enum<_Tp>::value>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2318:3: error: template with C linkage
 2318 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2323:3: error: template with C linkage
 2323 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2328:3: error: template with C linkage
 2328 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2334:3: error: template with C linkage
 2334 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2343:3: error: template with C linkage
 2343 |   template<typename _Signature>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2357:3: error: template with C linkage
 2357 |   template<typename _Tp, typename _Tag>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2364:5: error: template with C linkage
 2364 |     template<typename _Fp, typename _Tp1, typename... _Args>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2369:5: error: template with C linkage
 2369 |     template<typename...>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2373:3: error: template with C linkage
 2373 |   template<typename _MemPtr, typename _Arg, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2383:5: error: template with C linkage
 2383 |     template<typename _Fp, typename _Tp1, typename... _Args>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2388:5: error: template with C linkage
 2388 |     template<typename...>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2392:3: error: template with C linkage
 2392 |   template<typename _MemPtr, typename _Arg, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2402:5: error: template with C linkage
 2402 |     template<typename _Fp, typename _Tp1>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2407:5: error: template with C linkage
 2407 |     template<typename, typename>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2411:3: error: template with C linkage
 2411 |   template<typename _MemPtr, typename _Arg>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2421:5: error: template with C linkage
 2421 |     template<typename _Fp, typename _Tp1>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2426:5: error: template with C linkage
 2426 |     template<typename, typename>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2430:3: error: template with C linkage
 2430 |   template<typename _MemPtr, typename _Arg>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2437:3: error: template with C linkage
 2437 |   template<typename _MemPtr, typename _Arg>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2440:3: error: template with C linkage
 2440 |   template<typename _Res, typename _Class, typename _Arg>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2452:3: error: template with C linkage
 2452 |   template<typename _MemPtr, typename _Arg, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2455:3: error: template with C linkage
 2455 |   template<typename _Res, typename _Class, typename _Arg, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2471:3: error: template with C linkage
 2471 |   template<typename _Tp, typename _Up = __remove_cvref_t<_Tp>>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2477:3: error: template with C linkage
 2477 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2483:3: error: template with C linkage
 2483 |   template<bool, bool, typename _Functor, typename... _ArgTypes>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2489:3: error: template with C linkage
 2489 |   template<typename _MemPtr, typename _Arg>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2495:3: error: template with C linkage
 2495 |   template<typename _MemPtr, typename _Arg, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2504:5: error: template with C linkage
 2504 |     template<typename _Fn, typename... _Args>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2509:5: error: template with C linkage
 2509 |     template<typename...>
      |     ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2513:3: error: template with C linkage
 2513 |   template<typename _Functor, typename... _ArgTypes>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2521:3: error: template with C linkage
 2521 |   template<typename _Functor, typename... _ArgTypes>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2534:3: error: template with C linkage
 2534 |   template<typename _Functor, typename... _ArgTypes>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2541:3: error: template with C linkage
 2541 |   template<size_t _Len, size_t _Align =
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2545:3: error: template with C linkage
 2545 |   template <size_t _Len, typename... _Types>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2549:3: error: template with C linkage
 2549 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2553:3: error: template with C linkage
 2553 |   template<bool _Cond, typename _Tp = void>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2557:3: error: template with C linkage
 2557 |   template<bool _Cond, typename _Iftrue, typename _Iffalse>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2561:3: error: template with C linkage
 2561 |   template<typename... _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2565:3: error: template with C linkage
 2565 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2569:3: error: template with C linkage
 2569 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2576:3: error: template with C linkage
 2576 |   template<typename...> using void_t = void;
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2580:3: error: template with C linkage
 2580 |   template<typename _Default, typename _AlwaysVoid,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2589:3: error: template with C linkage
 2589 |   template<typename _Default, template<typename...> class _Op,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2598:3: error: template with C linkage
 2598 |   template<typename _Default, template<typename...> class _Op,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2603:3: error: template with C linkage
 2603 |   template<typename _Default, template<typename...> class _Op,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2624:3: error: template with C linkage
 2624 |   template <typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2627:3: error: template with C linkage
 2627 |   template <typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2630:3: error: template with C linkage
 2630 |   template<typename... _Elements>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2633:3: error: template with C linkage
 2633 |   template<typename>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2637:3: error: template with C linkage
 2637 |   template<typename... _Tps>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2642:3: error: template with C linkage
 2642 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2647:3: error: template with C linkage
 2647 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2657:3: error: template with C linkage
 2657 |   template<typename _Tp, size_t _Nm>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2669:7: error: template with C linkage
 2669 |       template<typename _Tp, typename
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2673:7: error: template with C linkage
 2673 |       template<typename>
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2679:7: error: template with C linkage
 2679 |       template<typename _Tp>
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2684:7: error: template with C linkage
 2684 |       template<typename>
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2690:3: error: template with C linkage
 2690 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2697:3: error: template with C linkage
 2697 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2704:3: error: template with C linkage
 2704 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2709:3: error: template with C linkage
 2709 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2719:3: error: template with C linkage
 2719 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2728:3: error: template with C linkage
 2728 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2738:3: error: template with C linkage
 2738 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2743:3: error: template with C linkage
 2743 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2753:7: error: template with C linkage
 2753 |       template<typename _Tp, typename _Up, typename
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2759:7: error: template with C linkage
 2759 |       template<typename, typename>
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2765:7: error: template with C linkage
 2765 |       template<typename _Tp, typename _Up>
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2772:7: error: template with C linkage
 2772 |       template<typename, typename>
      |       ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2778:3: error: template with C linkage
 2778 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2786:3: error: template with C linkage
 2786 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2793:3: error: template with C linkage
 2793 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2801:3: error: template with C linkage
 2801 |   template<typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2809:3: error: template with C linkage
 2809 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2815:3: error: template with C linkage
 2815 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2822:3: error: template with C linkage
 2822 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2827:3: error: template with C linkage
 2827 |   template<typename _Tp, typename _Up>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2837:3: error: template with C linkage
 2837 |   template<typename _Result, typename _Ret,
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2842:3: error: template with C linkage
 2842 |   template<typename _Result, typename _Ret>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2852:3: error: template with C linkage
 2852 |   template<typename _Result, typename _Ret>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2879:3: error: template with C linkage
 2879 |   template<typename _Fn, typename... _ArgTypes>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2884:3: error: template with C linkage
 2884 |   template<typename _Fn, typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2892:3: error: template with C linkage
 2892 |   template<typename _Fn, typename _Tp, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2899:3: error: template with C linkage
 2899 |   template<typename _Fn, typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2906:3: error: template with C linkage
 2906 |   template<typename _Fn, typename _Tp>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2912:3: error: template with C linkage
 2912 |   template<typename _Fn, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2918:3: error: template with C linkage
 2918 |   template<typename _Result, typename _Fn, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2925:3: error: template with C linkage
 2925 |   template<typename _Fn, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/c++/10/type_traits:2930:3: error: template with C linkage
 2930 |   template<typename _Fn, typename... _Args>
      |   ^~~~~~~~
In file included from callback.cc:22:
../gconfmm/callback.h:25:1: note: 'extern "C"' linkage started here
   25 | extern "C"
      | ^~~~~~~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glib-2.0/gobject/gbinding.h:28,
                 from /usr/include/glib-2.0/glib-object.h:22,
                 from /usr/include/gconf/2/gconf/gconf-client.h:24,
                 from ../gconfmm/callback.h:27,
                 from callback.cc:22:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: *** [Makefile:531: callback.lo] Error 1
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[2]: *** Waiting for unfinished jobs....
make[2]: Entering directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
/bin/sh ../../libtool  --tag=CXX   --mode=compile i586-alt-linux-g++ -DHAVE_CONFIG_H   -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include  -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c -o client.lo client.cc
libtool: compile:  i586-alt-linux-g++ -DHAVE_CONFIG_H -I.. -I../.. -DG_LOG_DOMAIN=\"gconfmm\" -DGCONFMM_BUILD=1 -pthread -pthread -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/gconf/2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -pipe -frecord-gcc-switches -Wall -g -O2 -march=i586 -mtune=generic -c client.cc  -fPIC -DPIC -o .libs/client.o
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from ../gconfmm/client.h:31,
                 from client.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:139:10: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  139 |   GTime  mod_time; /* time of the modification */
      |          ^~~~~~~~
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/client.h:7,
                 from client.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from ../gconfmm/client.h:31,
                 from client.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:144:62: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  144 | GTime       gconf_meta_info_mod_time     (GConfMetaInfo *gcmi);
      |                                                              ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/client.h:7,
                 from client.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
In file included from /usr/include/gconf/2/gconf/gconf-schema.h:26,
                 from /usr/include/gconf/2/gconf/gconf.h:27,
                 from /usr/include/gconf/2/gconf/gconf-client.h:25,
                 from ../gconfmm/client.h:31,
                 from client.cc:4:
/usr/include/gconf/2/gconf/gconf-value.h:153:69: warning: 'GTime' is deprecated: Use 'GDateTime' instead [-Wdeprecated-declarations]
  153 |                                              GTime          mod_time);
      |                                                                     ^
In file included from /usr/include/glib-2.0/glib.h:43,
                 from /usr/include/glibmm-2.4/glibmm/thread.h:39,
                 from /usr/include/glibmm-2.4/glibmm.h:103,
                 from ../gconfmm/client.h:7,
                 from client.cc:4:
/usr/include/glib-2.0/glib/gdate.h:48:17: note: declared here
   48 | typedef gint32  GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
      |                 ^~~~~
make[2]: Leaving directory '/usr/src/RPM/BUILD/gconfmm-2.28.3/gconf/gconfmm'
make[1]: *** [Makefile:571: all-recursive] Error 1
make: *** [Makefile:426: all] Error 2
error: Bad exit status from /usr/src/tmp/rpm-tmp.9983 (%build)


RPM build errors:
    Bad exit status from /usr/src/tmp/rpm-tmp.9983 (%build)
Command exited with non-zero status 1
18.31user 1.99system 0:19.99elapsed 101%CPU (0avgtext+0avgdata 114032maxresident)k
0inputs+0outputs (0major+914120minor)pagefaults 0swaps
hsh-rebuild: rebuild of `libgconfmm2-2.28.3-alt1.src.rpm' failed.
Command exited with non-zero status 1
43.60user 7.13system 0:53.04elapsed 95%CPU (0avgtext+0avgdata 114032maxresident)k
496inputs+0outputs (0major+1262625minor)pagefaults 0swaps