[clang] [SystemZ][z/OS] Add visibility features for z/OS (eg. _Export, pragma export) (PR #111035)

[Erich Keane via cfe-commits]

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@@ -4504,6 +4504,11 @@ void Parser::ParseDeclarationSpecifiers(
       isInvalid = DS.setFunctionSpecNoreturn(Loc, PrevSpec, DiagID);
       break;
 
+    case tok::kw__Export:
+      // We're done with the declaration-specifiers.
+      goto DoneWithDeclSpec;
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erichkeane wrote:

Does this mean `_Export` has to be last?   Not a parser guy here, but this one doesn't feel right to me?  @aaronballman can you double check here?

https://github.com/llvm/llvm-project/pull/111035