Adds generator support for Xcode 5 xctest targets.

test/mac/xctest/App/Classes/AppDelegate.h

Index: test/mac/xctest/App/Classes/AppDelegate.h
diff --git a/test/library_dirs/subdir/mylib.cc b/test/mac/xctest/App/Classes/AppDelegate.h
similarity index 64%
copy from test/library_dirs/subdir/mylib.cc
copy to test/mac/xctest/App/Classes/AppDelegate.h
index 654f3d0e6cc8d265e2cc65708811374211a4607d..d4d9bf12c4ffabd13ca1e2fcf1190e30d5b5c19c 100644
--- a/test/library_dirs/subdir/mylib.cc
+++ b/test/mac/xctest/App/Classes/AppDelegate.h
@@ -1,9 +1,6 @@
 // Copyright (c) 2013 Google Inc. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-
-#include "mylib.h"
-
-std::string my_foo(int x) {
-  return std::string("world");
-}
+#import <Cocoa/Cocoa.h>
+@interface AppDelegate : NSObject <NSApplicationDelegate>
+@end