Gentoo's Bugzilla –
Attachment 909024 Details for
Bug 943784Ruby extensions can't be built with -std=gnu23 because of ANYARGS macro (dev-ruby/brotli-0.6.0 - [libtool] [gcc-15] /.../anyargs.h: error: passing argument 3 of rb_define_singleton_method_m1 from incompatible pointer type)