title: Undefined symbols for architecture i386
body: <p>I have downloaded the SDL Library, i created an Xcode project, but when i try to build the xcode return this error:</p>
  
  <pre><code>Undefined symbols for architecture i386:
    "_SDL_CreateMutex", referenced from:
        -[testViewController packet_queue_init:] in testViewController.o
    "_SDL_CreateCond", referenced from:
        -[testViewController packet_queue_init:] in testViewController.o
  ld: symbol(s) not found for architecture i386
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>how can i fix it?? </p>
  
  <p>thanks</p>