What you're seeing is most likely not bugs (it is clang after all), but the result of the much stricter default compilation settings in "zig cc" which tends to break a lot of C code that hasn't been checked against a static analyzer or ASAN before.

No, they were bugs in zig CC. They were things like linking against the wrong frameworks on macOS.

Ah alright, some of those macOS specific problems had been fixed a little while ago when work on the macOS parts of the zld linker happened. I still get an occasional "framework headers not found" on macOS in the current Zig head version, but after the first failure I never seem to be able to reproduce it. It also never happens when running in CI, so I'm not sure if it isn't actually a problem with my Xcode setup.

Possibly true, but bugs can be fixed. The potential is still there.