[clang] clang: Relax LangOpts checks when lexing quoted numbers during preprocessing (PR #95798)

[Aaron Ballman via cfe-commits]

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@@ -2068,7 +2068,8 @@ bool Lexer::LexNumericConstant(Token &Result, const char *CurPtr) {
   }
 
   // If we have a digit separator, continue.
-  if (C == '\'' && (LangOpts.CPlusPlus14 || LangOpts.C23)) {
+  if (C == '\'' &&
+      (LangOpts.CPlusPlus14 || LangOpts.C23 || ParsingPreprocessorDirective)) {
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AaronBallman wrote:

I'm not certain that's a pattern we should get into -- we don't want a `LangOption` per language feature shared between languages unless it's something the user can enable or disable themselves via the command line.

https://github.com/llvm/llvm-project/pull/95798