title: Multithreading libraries for Objective-C
body: <p>Excluding Cocoa (and its <code>NSThread</code>), what multithreading libraries would you recommend?</p>
  
  <p>The application's engine must run on multiple platforms (Windows, Linux, MacOS, iPhone), and  be multithreaded. Abstracting the library to compile against platform-specific MT libraries is possible, but incurs an extra layer of overhead and complexity.</p>