[libc-commits] [libc] [libc] fix -Wtype-limits in wctob (PR #74511)

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https://github.com/michaelrj-google approved this pull request.

This version is fine, though we could also static cast to an unsigned type and just check if the resulting value is less than 127. Either is fine, feel free to land.

https://github.com/llvm/llvm-project/pull/74511