anchor.diff:          '';
         };
   
  +      package = mkOption {
  +        type = types.package;
  +        default = pkgs.exim;
  +        defaultText = "pkgs.exim";
  +        description = ''
  +          The Exim derivation to use.
  +          This can be used to enable features such as LDAP or PAM support.
  +        '';
  +      };
  +
       };
   
     };
  
positive.code:       gid = config.ids.gids.exim;
      };
  
      security.wrappers.exim.source = "${exim}/bin/exim";
  
      systemd.services.exim = {
        description = "Exim Mail Daemon";
        wantedBy = [ "multi-user.target" ];
        restartTriggers = [ config.environment.etc."exim.conf".source ];
        serviceConfig = {
          ExecStart   = "${exim}/bin/exim -bdf -q30m";
          ExecReload  = "${coreutils}/bin/kill -HUP $MAINPID";
        };
        preStart = ''
  
negative.code: 
  let
    inherit (lib) mkIf mkOption singleton types;
    inherit (pkgs) coreutils;
    cfg = config.services.exim;
  in
  
  