Fix Clang's __DEPRECATED define to be controled by -Wdeprecated. This

matches GCC behavior which libstdc++ uses to limit #warning-based
messages about deprecation.

The machinery involves threading this through a new '-fdeprecated-macro'
flag for CC1. The flag defaults to "on", similarly to -Wdeprecated. We
turn the flag off in the driver when the warning is turned off (modulo
matching some GCC bugs). We record this as a language option, and key
the preprocessor on the option when introducing the define.

A separate flag rather than a '-D' flag allows us to properly represent
the difference between C and C++ builds (only C++ receives the define),
and it allows the specific behavior of following -Wdeprecated without
potentially impacting the set of user-provided macro flags.

llvm-svn: 130055

clang/lib/Frontend/InitPreprocessor.cpp

@@ -319,7 +319,8 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
 
   if (LangOpts.CPlusPlus) {
-    Builder.defineMacro("__DEPRECATED");
+    if (LangOpts.Deprecated)
+      Builder.defineMacro("__DEPRECATED");
     Builder.defineMacro("__GNUG__", "4");
     Builder.defineMacro("__GXX_WEAK__");
     if (LangOpts.GNUMode)