anchor.diff:  
     postInstall =
       (stdenv.lib.optionalString (withPlugin && builtins.elem stdenv.system platforms)
  -    (let hplip_arch =
  +    (let hplipArch =
             if stdenv.system == "i686-linux" then "x86_32"
             else if stdenv.system == "x86_64-linux" then "x86_64"
             else abort "Plugin platform must be i686-linux or x86_64-linux!";
  
positive.code:     sha256 = "1ahalw83xm8x0h6hljhnkknry1hny9flkrlzcymv8nmwgic0kjgs";
    };
  
    hplip_state =
      substituteAll
        {
          inherit version;
          src = ./hplip.state;
        };
  
    hplip_arch =
      {
        "i686-linux" = "x86_32";
        "x86_64-linux" = "x86_64";
  
negative.code: 
      mkdir -p $out/share/hplip/prnt/plugins
      for plugin in lj hbpl1; do
        cp $plugin-${hplipArch}.so $out/share/hplip/prnt/plugins
        ln -s $out/share/hplip/prnt/plugins/$plugin-${hplipArch}.so \
          $out/share/hplip/prnt/plugins/$plugin.so
      done
  
      mkdir -p $out/share/hplip/scan/plugins
      for plugin in bb_soap bb_marvell bb_soapht fax_marvell; do
        cp $plugin-${hplipArch}.so $out/share/hplip/scan/plugins
        ln -s $out/share/hplip/scan/plugins/$plugin-${hplipArch}.so \
          $out/share/hplip/scan/plugins/$plugin.so
      done
  
      mkdir -p $out/var/lib/hp
      cp ${hplipState} $out/var/lib/hp/hplip.state
  
      mkdir -p $out/etc/sane.d/dll.d
      mv $out/etc/sane.d/dll.conf $out/etc/sane.d/dll.d/hpaio.conf
  