anchor.diff:  
     package = pkgs.openntpd_nixos;
   
  -  cfgFile = pkgs.writeText "openntpd.conf" ''
  +  configFile = ''
       ${concatStringsSep "\n" (map (s: "server ${s}") cfg.servers)}
       ${cfg.extraConfig}
     '';
  
positive.code:       type = with types; lines;
        default = "";
        example = ''
          listen on 127.0.0.1 
          listen on ::1 
        '';
        description = ''
          Additional text appended to <filename>openntpd.conf</filename>.
  
negative.code:       before = [ "time-sync.target" ];
        after = [ "dnsmasq.service" "bind.service" "network-online.target" ];
        serviceConfig = {
          ExecStart = "${package}/sbin/ntpd -p ${pidFile} ${cfg.extraOptions}";
          Type = "forking";
          PIDFile = pidFile;
        };
  