Preprocessor: Don't define __STDC__ in -traditional-cpp mode.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127933 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/InitPreprocessor.cpp

@@ -253,7 +253,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   // These should all be defined in the preprocessor according to the
   // current language configuration.
-  if (!LangOpts.Microsoft)
+  if (!LangOpts.Microsoft && !LangOpts.TraditionalCPP)
     Builder.defineMacro("__STDC__");
   if (LangOpts.AsmPreprocessor)
     Builder.defineMacro("__ASSEMBLER__");