Recognize GNU attributes after 'enum class'.  Fixes the libc++ build.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159089 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Parser/cxx0x-attributes.cpp b/test/Parser/cxx0x-attributes.cpp
index db5eebf..a0b8467 100644
--- a/test/Parser/cxx0x-attributes.cpp
+++ b/test/Parser/cxx0x-attributes.cpp
@@ -207,3 +207,8 @@
   for ([[]] int n : { 1, 2, 3 }) {
   }
 }
+
+enum class __attribute__((visibility("hidden"))) SecretKeepers {
+  one, /* rest are deprecated */ two, three
+};
+enum class [[]] EvenMoreSecrets {};