[libc-commits] [libc] [libc] added btowc to wchar.h generated header (PR #124168)

[Nick Desaulniers via libc-commits]

https://github.com/nickdesaulniers approved this pull request.

LGTM (besides the point from the bot). Need me to merge this for you?

https://github.com/llvm/llvm-project/pull/124168