[libcxx-commits] [libcxx] [libc++] Use public os_sync API instead of private __ulock on newer Apple platforms (PR #202519)

[Louis Dionne via libcxx-commits]

ldionne wrote:

I'll check whether it would make sense to have a way to request not touching `errno` in `os_sync_wait_on_address`.

https://github.com/llvm/llvm-project/pull/202519