anchor.diff:      hardware.bluetooth.enable = mkDefault true;
       services.xserver.libinput.enable = mkDefault true; # for controlling touchpad settings via gnome control center
       services.udev.packages = [ pkgs.gnome3.gnome_settings_daemon ];
  +
  +    # If gnome3 is installed, build vim for gtk3 too.
  +    nixpkgs.config.vim.gui = "gtk3";
   
       fonts.fonts = [ pkgs.dejavu_fonts pkgs.cantarell_fonts ];
   
  
positive.code:       };
  
        debug = mkEnableOption "gnome-session debug messages";
      };  
  
      environment.gnome3.packageSet = mkOption {
        default = null;
  
negative.code:       description = "Which GNOME 3 package set to use.";
        apply = p: if p == null then pkgs.gnome3 else p;
      };
  
      environment.gnome3.excludePackages = mkOption {
        default = [];
        example = literalExample "[ pkgs.gnome3.totem ]";
  