Generalize future keyword compat diagnostics.

This, in preparation for the introduction of more new keywords in the
implementation of the C++ language, generalizes the support for future keyword
compat diagnostics (e.g., diag::warn_cxx11_keyword) by extending the
applicability of the relevant property in IdentifierTable with appropriate
renaming.

Patch by Hubert Tong!

llvm-svn: 237332
diff --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp
index 0a27c6a..629b236 100644
--- a/clang/lib/Basic/IdentifierTable.cpp
+++ b/clang/lib/Basic/IdentifierTable.cpp
@@ -35,7 +35,7 @@
   HasMacro = false;
   HadMacro = false;
   IsExtension = false;
-  IsCXX11CompatKeyword = false;
+  IsFutureCompatKeyword = false;
   IsPoisoned = false;
   IsCPPOperatorKeyword = false;
   NeedsHandleIdentifier = false;
@@ -170,7 +170,7 @@
   IdentifierInfo &Info =
       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
   Info.setIsExtensionToken(AddResult == KS_Extension);
-  Info.setIsCXX11CompatKeyword(AddResult == KS_Future);
+  Info.setIsFutureCompatKeyword(AddResult == KS_Future);
 }
 
 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative