[clang] [RFC] Add clang atomic control options and pragmas (PR #102569)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

As discussed in the RFC at LLVM discourse, close this PR and open another PR for implementing it as a compound statement attribute https://github.com/llvm/llvm-project/pull/114841

https://github.com/llvm/llvm-project/pull/102569