[clang] [Clang] Allow simpler visibility annotations when targeting win32 and mingw (PR #133699)

[Erich Keane via cfe-commits]

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@@ -4185,6 +4185,14 @@ def DLLExport : InheritableAttr, TargetSpecificAttr<TargetHasDLLImportExport> {
   let Documentation = [DLLExportDocs];
 }
 
+def DLLExportOnDecl : InheritableAttr, TargetSpecificAttr<TargetHasDLLImportExport> {
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erichkeane wrote:

Hmm... I'm not a huge fan of this TBH.  An attribute for the sole purpose of diagnostics is a little novel and not particularly in keeping with our "represent the AST" nature of attributes.  Is there really no way we can figure this out later?

https://github.com/llvm/llvm-project/pull/133699