The -fshort-wchar option causes wchar_t to become unsigned, in addition to being
16-bits in size.  Implement this by splitting WChar into two enums, like we have
for char.  This fixes a miscompmilation of XULRunner, PR8856.

llvm-svn: 122558
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index aa9046f..875c66c 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -756,7 +756,8 @@
   case BuiltinType::Int128: Out << "_L"; break;
   case BuiltinType::UInt128: Out << "_M"; break;
   case BuiltinType::Bool: Out << "_N"; break;
-  case BuiltinType::WChar: Out << "_W"; break;
+  case BuiltinType::WChar_S:
+  case BuiltinType::WChar_U: Out << "_W"; break;
 
   case BuiltinType::Overload:
   case BuiltinType::Dependent: