error: /usr/include/objc/objc-class.h: No such file or directory
<p>I am currently using blocks in my UIButton category.  However I have come across this error which I cannot solve:</p>

<blockquote>
  <p>error: /usr/include/objc/objc-class.h:
  No such file or directory</p>
</blockquote>

<p>This is the line of code that uses blocks:</p>

<pre><code>FTButtonBlock block = objc_getAssociatedObject(self, "buttonBlock");
</code></pre>
