[libc-commits] [libc] [libc] Add unistd overlay (PR #119312)

[Michael Jones via libc-commits]

https://github.com/michaelrj-google commented:

For the types, you should use the headers in `hdr/types/type_name.h` instead of `include/llvm-libc-types/type_name.h`. After that's fixed this looks fine to land.

https://github.com/llvm/llvm-project/pull/119312