If we see an invalid #ifdef  directive, enter a conditional compilation region
so that we don't emit an error on the #endif.  Suggestion by Neil.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@42258 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Preprocessor/ifdef-recover.c b/test/Preprocessor/ifdef-recover.c
new file mode 100644
index 0000000..2009514
--- /dev/null
+++ b/test/Preprocessor/ifdef-recover.c
@@ -0,0 +1,7 @@
+/* RUN: clang %s 2>&1 | grep error: | count 1
+ */
+
+#ifdef
+
+#endif
+