title: embedFonts complains about “Unknown device: pswrite”
body: <p>Running <code>embedFonts</code> on some EPS file I created, I get an error message:</p>
  
  <pre class="lang-none prettyprint-override"><code>&gt; embedFonts("foo.ps")
  Unknown device: pswrite
  Unrecoverable error: undefined in .uninstallpagedevice
  Operand stack:
      defaultdevice
  Error in embedFonts("foo.ps") : 
    status 1 in running command 'gs -dNOPAUSE -dBATCH -q -dAutoRotatePages=/None -sDEVICE=pswrite -sOutputFile=/tmp/Rtmp3Lv0dj/Rembed2cd86df573a1 '-sFONTPATH='  'foo.ps''
  </code></pre>
  
  <p>How can I avoid this error?</p>