Building vala with GCC 14 fails here:
https://build.opensuse.org/package/live_build_log/openSUSE:Factory:Staging:Gcc7/vala/standard/x86_64

Due to:

valacodecontext.c: In function 'vala_code_context_get_file_path':
valacodecontext.c:2669:33: error: assignment to 'gchar **' {aka 'char **'} from incompatible pointer type 'const gchar * const*' {aka 'const char * const*'} [-Wincompatible-pointer-types]
 2669 |                 _tmp4_ = _tmp3_ = g_get_system_data_dirs ();
      |

This affects many(all?) packages using Vala language.

It appears that it is fixed upstream https://gitlab.gnome.org/GNOME/vala/-/issues/1407 on latest version.
If not, use -fpermissive as mentioned by meta bug#1220571 until it is.