[libcxx-commits] [libcxx] [libc++] __need_infinity_nan doesn't work in non-gnu c++ standards (PR #172539)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 requested changes to this pull request.

Why are we introducing new `__need_` macros? They are a horrible mess and I don't see why they're necessary. If someone _really_ needs _just_ that declaration, why can't they include the some detail header instead of making life miserable for everyone?

https://github.com/llvm/llvm-project/pull/172539