[clang] Add clang atomic control options and attribute (PR #114841)

[Yaxun Liu via cfe-commits]

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@@ -4979,3 +4979,16 @@ def NoTrivialAutoVarInit: InheritableAttr {
   let Documentation = [NoTrivialAutoVarInitDocs];
   let SimpleHandler = 1;
 }
+
+def Atomic : StmtAttr {
+  let Spellings = [Clang<"atomic">];
+  let Args = [VariadicStringArgument<"Options">];
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yxsamliu wrote:

will use VariadicEnumArgument

https://github.com/llvm/llvm-project/pull/114841