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