install_package "yaml-0.1.6" "http://pyyaml.org/download/libyaml/yaml-0.1.6.tar.gz#5fe00cda18ca5daeb43762b80c38e06e" --if needs_yaml
install_git "rubinius-2.0.0-dev" "https://github.com/rubinius/rubinius.git" "master" rbx