Description of problem:
Package gnucash fails to build from source in Fedora rawhide.

Version-Release number of selected component (if applicable):
4.4-1.fc34

Steps to Reproduce:
koji build --scratch f34 gnucash-4.4-1.fc34.src.rpm

Additional info:
This package is tracked by Koschei. See:
https://koschei.fedoraproject.org/package/gnucash

In file included from /usr/include/glib-2.0/glib/gmacros.h:241,
                 from /usr/lib64/glib-2.0/include/glibconfig.h:9,
                 from /usr/include/glib-2.0/glib/gtypes.h:32,
                 from /usr/include/glib-2.0/glib/galloca.h:32,
                 from /usr/include/glib-2.0/glib.h:30,
                 from /builddir/build/BUILD/gnucash-4.4/libgnucash/core-utils/gnc-locale-utils.cpp:24:
/usr/include/c++/11/type_traits:3215:3: error: template with C linkage
 3215 |   template<typename _Tp>
      |   ^~~~~~~~
/builddir/build/BUILD/gnucash-4.4/libgnucash/core-utils/gnc-locale-utils.cpp:22:1: note: 'extern "C"' linkage started here
   22 | extern "C"
      | ^~~~~~~~~~
wrote `/builddir/build/BUILD/gnucash-4.4/x86_64-redhat-linux-gnu/lib64/guile/2.2/site-ccache/gnucash/json/parser.go'