title: iPhone SDK 4: weird compilation error, MPMoviePlayerController
body: <p>I have a viewController containing the following method:</p>
  
  <pre><code>- (IBAction) playMovie {
      NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"test" ofType:@"m4v"]];
  
      MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:url];
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayBackDidFinish:)
                                         name:MPMoviePlayerPlaybackDidFinishNotification
                                         object:moviePlayer];
  
      moviePlayer.controlStyle = MPMovieControlStyleNone;
      moviePlayer.shouldAutoplay = YES;
  
      [self.view addSubview:moviePlayer.view];
      [moviePlayer setFullscreen:YES animated:YES];
  }
  </code></pre>
  
  <p>I can't compile the code because of the error:</p>
  
  <p>Undefined symbols:</p>
  
  <pre><code>  "_MPMoviePlayerPlaybackDidFinishNotification", referenced from:
        _MPMoviePlayerPlaybackDidFinishNotification$non_lazy_ptr in AnotherViewController.o
       (maybe you meant: _MPMoviePlayerPlaybackDidFinishNotification$non_lazy_ptr)
    "_OBJC_CLASS_$_MPMoviePlayerController", referenced from:
        objc-class-ref-to-MPMoviePlayerController in AnotherViewController.o
  ld: symbol(s) not found
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>This message doesn't make sense to me.</p>
  
  <p>I was intended to use this method as a part of a view controller. Do I have to create a separate view controller for the player or it's not the case?</p>
  
  <p>I worked with SDK 3.1.2 when I created this project but the playMovie method was completely rewritten according to new API rules. The current SDK version is 4.0.1</p>