[libc-commits] [libc] [libc] clean up futex usage (PR #91163)

[Schrodinger ZHU Yifan via libc-commits]

SchrodingerZhu wrote:

In this case, I will merge this PR as it leaves the API to use realtime lock. Timespec conversion involves `clock_getime` which can be implemented separately in outer-level logic without pulling in `clock_gettime` dependency into `futex_utils`.

https://github.com/llvm/llvm-project/pull/91163