Add basic support for Microsoft enum forward declaration. 
Assigning an underlying integral type to an enum forward declaration will come in a next patch.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113716 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/MicrosoftExtensions.cpp b/test/SemaCXX/MicrosoftExtensions.cpp
index 93650a5..7cc1675 100644
--- a/test/SemaCXX/MicrosoftExtensions.cpp
+++ b/test/SemaCXX/MicrosoftExtensions.cpp
@@ -84,3 +84,7 @@
   h1<int>(&M::addP);
   h1(&M::subtractP);
 } 
+
+//MSVC allows forward enum declaration
+enum ENUM; // expected-warning {{forward references to 'enum' types are a Microsoft extension}}
+ENUM *var;