anchor.diff:  
       package = mkOption {
         type = types.path;
  -      description = "The Xwayland package";
  +      default = pkgs.xwayland.override (oldArgs: {
  +        inherit (cfg) defaultFontPath;
  +      });
  +      defaultText = literalExample ''
  +        pkgs.xwayland.override (oldArgs: {
  +          inherit (config.programs.xwayland) defaultFontPath;
  +        });
  +      '';
  +      description = "The Xwayland package to use.";
       };
   
     };
  
positive.code: {
    options.programs.xwayland = {
  
      enable = mkEnableOption ''
        Xwayland X server allows running X programs on a Wayland compositor.
      '';
  
      defaultFontPath = mkOption {
        type = types.str;
        default = optionalString config.fonts.fontDir.enable
          "/run/current-system/sw/share/X11/fonts";
        description = ''
          Default font path. Setting this option causes Xwayland to be rebuilt.
        '';
  
negative.code: 
      environment.systemPackages = [ cfg.package ];
  
    };
  }
  