install_package "yaml-0.1.6" "http://pyyaml.org/download/libyaml/yaml-0.1.6.tar.gz#5fe00cda18ca5daeb43762b80c38e06e" --if needs_yaml
install_package "openssl-1.0.1g" "https://www.openssl.org/source/openssl-1.0.1g.tar.gz#de62b43dfcd858e66a74bee1c834e959" mac_openssl --if has_broken_mac_openssl
install_package "ruby-2.0.0-rc2" "http://cache.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-rc2.tar.gz#9d5e6f26db7c8c3ddefc81fdb19bd41a" standard verify_openssl