[libcxx-commits] [libcxx] [libc++] Revert "Do not redeclare lgamma_r when targeting the LLVM C library (#102036) (PR #125587)

[Louis Dionne via libcxx-commits]

ldionne wrote:

My strong preference would be to include a standard header instead, but that would require LLVM libc to define its detection macro when such header is included.

I'd be okay with a partial revert only, but @jhuber6 would have to tell me what the check should be instead.

https://github.com/llvm/llvm-project/pull/125587