Revert "Move -fms-extensions predefined macros into InitPreprocessor"

This reverts commit r206413.

This was proposed before, but it's not clear if this is really a good
idea:
http://reviews.llvm.org/D3034

llvm-svn: 206415

clang/lib/Frontend/InitPreprocessor.cpp

@@ -507,19 +507,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     Builder.defineMacro("__private_extern__", "extern");
   }
 
-  if (LangOpts.MSCVersion != 0)
-    Builder.defineMacro("_MSC_VER", Twine(LangOpts.MSCVersion));
-
   if (LangOpts.MicrosoftExt) {
-    // Define feature support macros that MSVC provides.
-    Builder.defineMacro("_MSC_EXTENSIONS");
-
-    if (LangOpts.CPlusPlus11) {
-      Builder.defineMacro("_RVALUE_REFERENCES_V2_SUPPORTED");
-      Builder.defineMacro("_RVALUE_REFERENCES_SUPPORTED");
-      Builder.defineMacro("_NATIVE_NULLPTR_SUPPORTED");
-    }
-
     if (LangOpts.WChar) {
       // wchar_t supported as a keyword.
       Builder.defineMacro("_WCHAR_T_DEFINED");