Don't warn for unused macro when undef'ing it, if it comes from an included file. rdar://9745065

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134919 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Preprocessor/warn-macro-unused.c b/test/Preprocessor/warn-macro-unused.c
index 8a6d7c2..c33aeb5 100644
--- a/test/Preprocessor/warn-macro-unused.c
+++ b/test/Preprocessor/warn-macro-unused.c
@@ -1,5 +1,10 @@
 // RUN: %clang_cc1 %s -Wunused-macros -Dfoo -Dfoo -verify
 
+#include "warn-macro-unused.h"
+
 #define unused // expected-warning {{macro is not used}}
 #define unused
 unused
+
+// rdar://9745065
+#undef unused_from_header // no warning