anchor.diff:        '';
       };
   
  +    nix.version = mkOption {
  +      type = types.str;
  +      default = "<unknown>";
  +      example = "1.11.6";
  +      description = "The version of nix. Used to determine what settings to configure in nix.conf";
  +    };
  +
       nix.useDaemon = mkOption {
         type = types.bool;
         default = false;
  
positive.code:     nix.package = mkIf (config.system.stateVersion < 3)
        "/nix/var/nix/profiles/default";
  
      environment.systemPackages = mkIf (isDerivation cfg.package)
        [ cfg.package ];
  
  
negative.code: let
    cfg = config.nix;
  
    isNix20 = versionAtLeast (cfg.version or "<unknown>") "1.12pre";
  
    nixConf =
      let
  