title: Building passenger apache2 module: no such file to load -- rubygems builder
body: <p>I want to build passenger-3.0.19 apache2 module on a debian squeeze server. After calling passenger-install-apache2-module as root i get the following error message:</p>
  
  <pre><code>Compiling and installing Apache 2 module...
  cd /usr/lib/ruby/gems/1.8/gems/passenger-3.0.19
  /usr/bin/ruby1.8 /usr/bin/rake apache2:clean apache2 RELEASE=yes
  # /usr/bin/ruby1.8 /usr/bin/rake apache2:clean apache2 RELEASE=yes
  rake aborted!
  no such file to load -- rubygems/builder
  </code></pre>
  
  <p>Where is the problem? How can i fix this? Using passenger-install-apache2-module --trace doesn't work (for full stacktrace).</p>
  
  <p><img src="https://i.stack.imgur.com/1ZP2P.png" alt="no such file to load -- rubygems/builder"></p>