anchor.diff:    enableParallelBuilding = true;
   
     doCheck = true;
  -
  -  preFixup = ''
  -    wrapProgram "$out/bin/simple-scan" \
  -      --prefix XDG_DATA_DIRS : "$GSETTINGS_SCHEMAS_PATH"
  -  '';
   
     meta = with stdenv.lib; {
       inherit version;
  
positive.code: { stdenv, fetchurl, cairo, colord, glib, gtk3, gusb, intltool, itstool, libusb
  , libxml2, makeWrapper, pkgconfig, saneBackends, systemd, vala }:
  
  let version = "3.19.2"; in
  stdenv.mkDerivation rec {
  
negative.code: 
    buildInputs = [ cairo colord glib gusb gtk3 libusb libxml2 saneBackends
      systemd vala ];
    nativeBuildInputs = [ intltool itstool pkgconfig wrapGAppsHook ];
  
    configureFlags = [ "--disable-packagekit" ];
  
  