[clang] [clang] Allow attributes on first constructor argument in pre-C++11 (PR #157300)

[Shafik Yaghmour via cfe-commits]

================
@@ -6007,10 +6007,9 @@ bool Parser::isConstructorDeclarator(bool IsUnqualified, bool DeductionGuide,
 
   // A C++11 attribute here signals that we have a constructor, and is an
   // attribute on the first constructor parameter.
-  if (getLangOpts().CPlusPlus11 &&
-      isCXX11AttributeSpecifier(/*Disambiguate*/ false,
+  if (isCXX11AttributeSpecifier(/*Disambiguate*/ false,
----------------
shafik wrote:

```suggestion
  if (isCXX11AttributeSpecifier(/*Disambiguate=*/false,
```

https://github.com/llvm/llvm-project/pull/157300