[clang] [Clang] [Parser] Fixing all callers of `ParseExternalDeclaration` that didn't parse gnu attributes (PR #117148)

[Mathys Gasnier via cfe-commits]

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@@ -480,10 +468,7 @@ Decl *Parser::ParseExportDeclaration() {
 
   while (!tryParseMisplacedModuleImport() && Tok.isNot(tok::r_brace) &&
          Tok.isNot(tok::eof)) {
-    ParsedAttributes DeclAttrs(AttrFactory);
-    MaybeParseCXX11Attributes(DeclAttrs);
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Mathys-Gasnier wrote:

Probably not, some place still use it, and we aren't able to replace it with the new function due to branching depending on different tokens. For example see ParseDeclCXX.cpp in `ParseLinkage`

https://github.com/llvm/llvm-project/pull/117148