{stdenv, fetchurl, hotplugSupport ? false, libusb ? null,
	gt68xxFirmware ? null}:

assert hotplugSupport -> stdenv.system == "i686-linux";

stdenv.mkDerivation {
  name = "sane-backends-1.0.20";
  
  src = fetchurl {
    url = ftp://ftp.sane-project.org/pub/sane/sane-backends-1.0.20/sane-backends-1.0.20.tar.gz;
    sha256 = "0fixmq3jbz77zcy2cikb882kz8bq3n40n0jaykiczfcjc4g57ccg";
  };
  
  udevSupport = hotplugSupport;

  buildInputs = if libusb != null then [libusb] else [];

  postInstall = ''
    if test "$udevSupport" = "1"; then
      ensureDir $out/etc/udev/rules.d/
      cp tools/udev/libsane.rules $out/etc/udev/rules.d/60-libsane.rules
    fi
  '';

  preInstall =
    if gt68xxFirmware != null then 
      "mkdir -p \${out}/share/sane/gt68xx ; ln -s " +  
      (gt68xxFirmware {inherit fetchurl;}) +
      "  \${out}/share/sane/gt68xx/PS1fw.usb "
    else "";
}