[clang] [Clang] Introduce scoped variants of GNU atomic functions (PR #72280)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> Overall I think it is the right way to go. Memory scope has been used by different offloading languages and the atomic clang builtins are essentially the same. Adding a generic clang atomic builtins with memory scope allows code sharing among offloading languages.

I agree, I'm hoping to hear something from people more familiar with C/C++ or GNU stuff to see if they agree with this direction. Also it might help to decide on some better names for the memory scopes.

https://github.com/llvm/llvm-project/pull/72280