title: bundle install / update: libv8 (therubyracer) installation fails (with native extensions)
body: <p>I recently wanted to update my gem bundle but ran into installation problems with libv8 (requirement for therubyracer):</p>
  
  <pre>Installing libv8 (3.3.10.3) with native extensions /usr/local/rvm/rubies/ruby-1.9.3-head/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:552:in `rescue in block in build_extensions': ERROR: Failed
   to build gem native extension. (Gem::Installer::ExtensionBuildError)
  
          /usr/local/rvm/rubies/ruby-1.9.3-head/bin/ruby extconf.rb 
  Checking for Python...*** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of
  necessary libraries and/or headers.  Check the mkmf.log file for more
  details.  You may need configuration options.
  </pre>
  
  <p>I have found the <a href="https://github.com/cowboyd/therubyracer/issues/126">issue report on therubyracer github site</a> and it suggests to uninstall and reinstall libv8, but this does not work on my Ubuntu 11.04 machine. Any ideas - or am I stuck with the old version for a while?</p>