[libc-commits] [libc] [libc] Some more MSVC compatibility in src/__support. (PR #158108)

[Joseph Huber via libc-commits]

https://github.com/jhuber6 commented:

So, MSVC does not have `__has_builtin`? I remember we used to have `LIBC_HAS_BUILTIN` as a workaround that returned zero if not. Maybe we need to bring that back. Every path should have a valid fallback so a lot of this should be automatic if we don't have the builtin.

https://github.com/llvm/llvm-project/pull/158108