title: How to install libffi-dev on Mac OS X
body: <p>I am trying to implement micropython on unix, which requires <code>libffi-dev</code>. I installed in this way <code>brew install libffi-dev</code>. But it seems that there is no libffi-dev can be found. </p>
  
  <p>Is there any way to install <code>libffi-dev</code> on Mac os. Thank you.</p>