[clang] [OpenACC] Add 'clause' parsing infrastructure plus a few clauses (PR #75052)

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@@ -262,12 +291,52 @@ OpenACCDirectiveKind ParseOpenACCDirectiveKind(Parser &P) {
   return DirKind;
 }
 
+bool ParseOpenACCClause(Parser &P) {
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cor3ntin wrote:

Thanks

https://github.com/llvm/llvm-project/pull/75052