ERROR: Error al instalar capybara-webkit:

¿Alguna sugerencia sobre cómo solucionarlo? gem install capybara-webkit -v '0.11.0' Building native extensions. This could take a while... ERROR: Error installing capybara-webkit: ERROR: Failed to build gem native extension. /home/durrantm/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb sh:...