title: Where does /usr/include/mach-o/loader.h come from?
body: <p>It seems that some of my Mac OS X systems have /usr/include/mach-o/loader.h and others don't. I'm confused because this file is documented here:</p>
  
  <p><a href="https://developer.apple.com/library/mac/#documentation/developertools/conceptual/MachORuntime/Reference/reference.html" rel="nofollow">https://developer.apple.com/library/mac/#documentation/developertools/conceptual/MachORuntime/Reference/reference.html</a></p>
  
  <p>For example:</p>
  
  <pre><code>...Declared in /usr/include/mach-o/loader.h. See also mach_header_64.
  </code></pre>
  
  <p>Does anyone know if this file was removed on any newer versions of Mac OS X? Or if I need to install a special SDK to get it?</p>