Fix PR2086.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@47551 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Preprocessor/pr2086.h b/test/Preprocessor/pr2086.h
new file mode 100644
index 0000000..b98b996
--- /dev/null
+++ b/test/Preprocessor/pr2086.h
@@ -0,0 +1,6 @@
+#ifndef test
+#endif
+
+#ifdef test
+#undef test
+#endif