[libc] [llvm] Implement pkey_alloc/free/get/set/mprotect for x86_64 linux (PR #162362)

[Michael Jones via llvm-commits]

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

Overall this looks good, but you need to update the headergen file in `include/sys/mman.yaml`

https://github.com/llvm/llvm-project/pull/162362