Using NSUserDefaults to log background pushes, useful for debugging newsstand

gistfile1.m

#define NSDLOG(fmt, ...)    if (![[NSUserDefaults standardUserDefaults] valueForKey: @"LOG"]) { \
                                [[NSUserDefaults standardUserDefaults] setValue: @"" forKey: @"LOG"]; \
                                [[NSUserDefaults standardUserDefaults] synchronize]; \
                            } \
                            [[NSUserDefaults standardUserDefaults] setValue: [[[NSUserDefaults standardUserDefaults] valueForKey: @"LOG"] stringByAppendingFormat: [@"\n" stringByAppendingString: fmt], ##__VA_ARGS__] forKeyPath: @"LOG"]; \
                            [[NSUserDefaults standardUserDefaults] synchronize];