Add the Microsoft __is_interface_class type trait.
Patch by Andy Gibbs!

llvm-svn: 164591
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index 01ab0e4..40c4eee 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -782,6 +782,7 @@
   case tok::kw___is_convertible_to:
   case tok::kw___is_empty:
   case tok::kw___is_enum:
+  case tok::kw___is_interface_class:
   case tok::kw___is_final:
   case tok::kw___is_literal:
   case tok::kw___is_literal_type: