anchor.diff:  
         packageFun = mkOption {
           default = pkgs: pkgs.xorg;
  +        merge = backwardPkgsFunOldMerge;
           description = "
             Alternative X.org package to use. For 
             example, you can replace individual drivers.
  
positive.code: 
  let
    inherit (pkgs.lib) mkOption;
  in
  
  {
  
negative.code:     extraPackages = mkOption {
        default = pkgs: [];
        example = pkgs: [pkgs.firefox pkgs.thunderbird];
        merge = backwardPkgsFunListOldMerge;
        description = "
          This option allows you to add additional packages to the system
          path.  These packages are automatically available to all users,
  