anchor.diff:  
       system.build.units = cfg.units;
   
  -    system.nssModules = [ systemd.out ];
  +    system.nssModules = [ cfg.package.out ];
       system.nssDatabases = {
         hosts = (mkMerge [
           (mkOrder 400 ["mymachines"]) # 400 to ensure it comes before resolve (which is mkBefore'd)
  
positive.code: let
  
    cfg = config.systemd;
  
    systemd = cfg.package;
  
    inherit (systemdUtils.lib)
      generateUnits
  
negative.code:       ]);
      };
  
      environment.systemPackages = [ cfg.package ];
  
      environment.etc = let
        # generate contents for /etc/systemd/system-${type} from attrset of links and packages
  