Fixes the test.

llvm-svn: 92875
diff --git a/clang/test/Rewriter/weak_byref_objects.m b/clang/test/Rewriter/weak_byref_objects.m
index 509cb4d..583afcc 100644
--- a/clang/test/Rewriter/weak_byref_objects.m
+++ b/clang/test/Rewriter/weak_byref_objects.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fblocks -rewrite-objc %s -o -
+// RUN: %clang_cc1 -fblocks -fobjc-gc -rewrite-objc %s -o -
 
 #define nil 0
 int main() {