title: Brew doctor: dyld: Library not loaded & Error: No available formula for zlib
body: <p>When I <code>brew doctor</code> I get the following errors:</p>
  
  <pre><code>dyld: Library not loaded: /usr/lib/libltdl.7.dylib
    Referenced from: /usr/local/bin/php
    Reason: image not found
  Error: No available formula for zlib
  </code></pre>
  
  <p>The file <code>libltdl.7.dylib</code> is not in my /usr/lib directory, but there are several other <code>.dylib</code> files.</p>
  
  <p>I'm running 10.8.1 with the latest version of Xcode (4.4.1) and its Command Line Tools installed.</p>
  
  <p>Any idea how to solve these errors? </p>