title: p4merge and Git 1.8.3
body: <p>How can I config <code>git</code> to use <code>p4merge</code> as my <code>mergetool</code>?</p>
  
  <p>Next is my current situation:</p>
  
  <pre><code>$ git --version
  git version 1.8.3.msysgit.0
  
  $ git mergetool
  
  This message is displayed because 'merge.tool' is not configured.
  See 'git mergetool --tool-help' or 'git help config' for more details.
  'git mergetool' will now attempt to use one of the following tools:
  tortoisemerge emerge vimdiff
  No known merge tool is available.
  </code></pre>