Advertize support for constexpr.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150524 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 3fe3ab3..a285c30 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -638,7 +638,7 @@
            .Case("cxx_atomic", LangOpts.CPlusPlus0x)
            .Case("cxx_attributes", LangOpts.CPlusPlus0x)
            .Case("cxx_auto_type", LangOpts.CPlusPlus0x)
-         //.Case("cxx_constexpr", false);
+           .Case("cxx_constexpr", LangOpts.CPlusPlus0x)
            .Case("cxx_decltype", LangOpts.CPlusPlus0x)
            .Case("cxx_default_function_template_args", LangOpts.CPlusPlus0x)
            .Case("cxx_defaulted_functions", LangOpts.CPlusPlus0x)