anchor.diff:  
     buildInputs =
       [ imagemagickBig pkgconfig python pygtk perl libX11
  -      libv4l qt4 lzma gtk2 autoreconfHook ];
  +      lzma autoreconfHook ] ++
  +    stdenv.lib.optionals enableVideo [ libv4l gtk2 qt4 ];
  +
  +  configureFlags = stdenv.lib.optionals (!enableVideo) [
  +    "--disable-video" "--without-gtk" "--without-qt"
  +  ];
   
     hardeningDisable = [ "fortify" ];
   
  
positive.code:       Code.
      '';
      maintainers = with maintainers; [ raskin ];
      platforms = platforms.linux;
      license = licenses.lgpl21;
      homepage = http://zbar.sourceforge.net/;
    };
  
negative.code: { stdenv, fetchurl, imagemagickBig, pkgconfig, python2Packages, perl
  , libX11, libv4l, qt4, lzma, gtk2, fetchpatch, autoreconfHook
  , enableVideo ? stdenv.isLinux
  }:
  
  let
  