/// $PackageInfo: require_system("darwin") libmaxminddb pkg-config
/// $PackageInfo: require_system("debian" "9.0") libmaxminddb-dev pkg-config
/// $PackageInfo: require_system("ubuntu" "16.04") libmaxminddb-dev pkg-config
/// $PackageInfo: require_system("darwin") libmaxminddb pkg-config
/// $PackageInfo: require_system("debian" "9.0") libmaxminddb-dev pkg-config
/// $PackageInfo: require_system("ubuntu" "16.04") libmaxminddb-dev pkg-config