anchor.diff:      name = "cups-progs";
       paths =
         [ cups additionalBackends cups_filters pkgs.ghostscript ]
  +      ++ optional cfg.gutenprint gutenprint
         ++ cfg.drivers;
       pathsToLink = [ "/lib/cups" "/share/cups" "/bin" "/etc/cups" ];
       postBuild = cfg.bindirCmds;
  
positive.code:         '';
        };
  
        drivers = mkOption {
          type = types.listOf types.path;
          default = [];
  
negative.code: 
  let
  
    inherit (pkgs) cups cups-pk-helper cups_filters gutenprint;
  
    cfg = config.services.printing;
  
  