[libc-commits] [libc] [libc] Add `locale.h` and related stubs (PR #97494)

[Petr Hosek via libc-commits]

petrhosek wrote:

I'd suggest omitting all of the `TODO` and `HACK` comments. Those are only meaningful if the plan is to eventually address them, but for LLVM libc the current consensus is that we don't intend to provide a complete locale implementation and what is in this PR is likely what we're going support in the long term. This approach is also used by other C library implementations such as musl.

https://github.com/llvm/llvm-project/pull/97494