[libcxx-commits] [libcxx] [libc++] Prevent cycle from including __mbstate_t.h within wchar.h (PR #200940)

[Nikolas Klauser via libcxx-commits]

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

Why do we need to include `<__mbstate_t.h>` at all?

https://github.com/llvm/llvm-project/pull/200940