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

[Ian Anderson via libcxx-commits]

ian-twilightcoder wrote:

> 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?

For consistency, that's just how partial inclusion is done in gcc and clang. Totally agree they're weird and sucky and I don't know why gcc didn't just make detail headers when they first discovered the need (which is mostly POSIX driven, as I understand it) for partial inclusion.

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