C1X: implement generic selections

As an extension, generic selection support has been added for all
supported languages.  The syntax is the same as for C1X.

llvm-svn: 129554
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index be17ccf..752163a 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -1750,6 +1750,7 @@
   case Expr::ChooseExprClass:
   case Expr::CompoundLiteralExprClass:
   case Expr::ExtVectorElementExprClass:
+  case Expr::GenericSelectionExprClass:
   case Expr::ObjCEncodeExprClass:
   case Expr::ObjCIsaExprClass:
   case Expr::ObjCIvarRefExprClass: