https://koji.fedoraproject.org/koji/buildinfo?buildID=2157616

In file included from /usr/include/glib-2.0/glib/giochannel.h:36,
                 from /usr/include/glib-2.0/glib.h:56,
                 from /usr/include/glib-2.0/gmodule.h:30,
                 from /builddir/build/BUILD/gnucash-4.13/libgnucash/gnc-module/gnc-module.c:31:
/builddir/build/BUILD/gnucash-4.13/libgnucash/gnc-module/gnc-module.c: In function 'gnc_module_system_search_dirs':
/usr/include/glib-2.0/glib/gstring.h:72:5: error: ignoring return value of 'g_string_free_and_steal' declared with attribute 'warn_unused_result' [-Werror=unused-result]
   68 |   (__builtin_constant_p (free_segment) ?        \
      |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |     ((free_segment) ?                           \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |       (g_string_free) ((str), (free_segment)) : \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   71 |       g_string_free_and_steal (str))            \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   72 |     :                                           \
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   73 |     (g_string_free) ((str), (free_segment)))
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builddir/build/BUILD/gnucash-4.13/libgnucash/gnc-module/gnc-module.c:111:17: note: in expansion of macro 'g_string_free'
  111 |                 g_string_free(token, FALSE);
      |                 ^~~~~~~~~~~~~
gmake[2]: Leaving directory '/builddir/build/BUILD/gnucash-4.13/redhat-linux-build'
/usr/bin/gmake  -f libgnucash/tax/CMakeFiles/scm-tax-us-1-links.dir/build.make libgnucash/tax/CMakeFiles/scm-tax-us-1-links.dir/build
/usr/include/glib-2.0/glib/gstring.h:72:5: error: ignoring return value of 'g_string_free_and_steal' declared with attribute 'warn_unused_result' [-Werror=unused-result]
   68 |   (__builtin_constant_p (free_segment) ?        \
      |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   69 |     ((free_segment) ?                           \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   70 |       (g_string_free) ((str), (free_segment)) : \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   71 |       g_string_free_and_steal (str))            \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   72 |     :                                           \
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   73 |     (g_string_free) ((str), (free_segment)))
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builddir/build/BUILD/gnucash-4.13/libgnucash/gnc-module/gnc-module.c:130:9: note: in expansion of macro 'g_string_free'
  130 |         g_string_free(token, FALSE);
      |         ^~~~~~~~~~~~~