anchor.diff:  
       enableIntel4965AGNFirmware = mkOption {
         default = false;
  +      merge = obsoleteMerge;
         description = "
           This option enables automatic loading of the firmware for the Intel
           PRO/Wireless 4965AGN.
  
positive.code:   inherit (pkgs.lib) mkOption;
    inherit (builtins) head tail;
  
    # temporary modifications.
    # backward here means that expression could either be a value or a
    # function which expects to have a pkgs argument.
    optionalPkgs = x:
      if __isFunction x then x pkgs else x;
  
    backwardPkgsFunListMerge = name: list:
      pkgs.lib.concatMap optionalPkgs list;
  
    backwardPkgsFunMerge = name: list:
      if list != [] && tail list == []
      then optionalPkgs (head list)
      else abort "${name}: Defined at least twice.";
  in
  
  {
  
negative.code: 
      enableIntel3945ABGFirmware = mkOption {
        default = false;
        merge = obsoleteMerge;
        description = "
          This option enables automatic loading of the firmware for the Intel
          PRO/Wireless 3945ABG.
  