def os_option(option, *args)
      options = args.pop if args.last.is_a?(Hash)
      options ||= {}
      args.push options.merge(os_prefix: true)
      option option, *args
    end
def os_option(option, *args)
      options = args.pop if args.last.is_a?(Hash)
      options ||= {}
      args.push options.merge(os_prefix: true)
      option option, *args
    end
An +os_option+ has automatically a OS-dependent prefix