[clang] [clang]Implement the c23 stdc bit builtins (PR #185978)

[Aaron Ballman via cfe-commits]

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

Given that we're kicking some work to a follow-up, I think this is looking pretty close to ready. Please give some time for @efriedma-quic to sign off as well on the codegen behavior before landing.

Thank you for the work on this!

https://github.com/llvm/llvm-project/pull/185978