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

llvm-svn: 164591
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 9b95641..37cdd14 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -1208,6 +1208,7 @@
   case tok::kw___is_class:
   case tok::kw___is_empty:
   case tok::kw___is_enum:
+  case tok::kw___is_interface_class:
   case tok::kw___is_literal:
   case tok::kw___is_arithmetic:
   case tok::kw___is_integral: