[libc-commits] [libc] [libc][errno] Use macro instead of system header (PR #91150)

[via libc-commits]

https://github.com/lntue requested changes to this pull request.

Thanks for fixing the `errno` header issue!  Do you mind adding a proxy header `libc/hdr/errno_macros.h` to separate overlay and full build modes, similar to `libc/hdr/fenv_macros.h`?

https://github.com/llvm/llvm-project/pull/91150