[clang] [Clang] Add __has_target_builtin macro (PR #126324)

[Aaron Ballman via cfe-commits]

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@@ -1797,55 +1798,62 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
                                            diag::err_feature_check_malformed);
         return II && HasExtension(*this, II->getName());
       });
-  } else if (II == Ident__has_builtin) {
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AaronBallman wrote:

I'd prefer it; it makes it easier to see what's actually changed. But if that's a PITA, I won't insist.

https://github.com/llvm/llvm-project/pull/126324