[clang] Fix INF/NAN warning. (PR #80290)

[Aaron Ballman via cfe-commits]

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@@ -3288,7 +3288,7 @@ void Preprocessor::HandleIfdefDirective(Token &Result,
     return;
   }
 
-  emitMacroExpansionWarnings(MacroNameTok);
+  emitMacroExpansionWarnings(MacroNameTok, true);
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AaronBallman wrote:

You'll still need this one because that's what controls silencing the diagnostic in an ifndef.

https://github.com/llvm/llvm-project/pull/80290