Adds generator support for Xcode 5 xctest targets.

test/mac/xctest/Shared/Shared.m

Index: test/mac/xctest/Shared/Shared.m
diff --git a/test/prune_targets/lib2.cc b/test/mac/xctest/Shared/Shared.m
similarity index 60%
copy from test/prune_targets/lib2.cc
copy to test/mac/xctest/Shared/Shared.m
index aed394afcff768af538513e67e47170f954a36c3..e30f6159ce022009084c08fde6a65a8247aa69d0 100644
--- a/test/prune_targets/lib2.cc
+++ b/test/mac/xctest/Shared/Shared.m
@@ -1,6 +1,9 @@
 // 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.
-
-void libfunc2() {
+#import "Shared.h"
+@implementation Shared
+- (NSString *)description {
+  return @"My shared object";
 }
+@end