[libcxx-commits] [libcxx] [libcxx] Define _LIBCPP_HAS_C8RTOMB_MBRTOC8 for picolibc (PR #152724)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 commented:

I think it would be better to refactor `_LIBCPP_HAS_C8RTOMB_MBRTOC8` so that it's true unless we know it to be false (and also unconditionally make it true with Clang).

https://github.com/llvm/llvm-project/pull/152724