install_package "yaml-0.1.6" "http://pyyaml.org/download/libyaml/yaml-0.1.6.tar.gz#7da6971b4bd08a986dd2a61353bc422362bd0edcc67d7ebaac68c95f74182749" --if needs_yaml
install_package "openssl-1.0.1p" "https://www.openssl.org/source/openssl-1.0.1p.tar.gz#bd5ee6803165c0fb60bbecbacacf244f1f90d2aa0d71353af610c29121e9b2f1" mac_openssl --if has_broken_mac_openssl
install_package "ruby-2.1.0-preview1" "https://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.0-preview1.tar.gz#747472fb33bcc529f1000e5320605a7e166a095d3805520b989e73b33c05b046" standard verify_openssl