Make -mms-bitfields behave consistently.

Patch by Jeremiah Zanin.

llvm-svn: 165849
diff --git a/clang/test/Sema/pragma-ms_struct.c b/clang/test/Sema/pragma-ms_struct.c
index d76ee8b..6533320 100644
--- a/clang/test/Sema/pragma-ms_struct.c
+++ b/clang/test/Sema/pragma-ms_struct.c
@@ -31,6 +31,12 @@
                    unsigned long bf_2 : 12;
 } __attribute__((ms_struct)) t2;
 
+enum
+{
+  A = 0,
+  B,
+  C
+} __attribute__((ms_struct)) e1; // expected-warning {{'ms_struct' attribute ignored}}
 
 // rdar://10513599
 #pragma ms_struct on