title: Hg clone fails with "Cannot connect to X server"
body: <p>On a machine where I have only SSH access, <code>hg clone</code> suddenly fails:</p>
  
  <pre><code>hg clone http://cls@&lt;repopath&gt;
  : cannot connect to X server 
  </code></pre>
  
  <p>Why is X server involved at all? How can I fix this?</p>