anchor.diff:      cairo
       exiv2
       ffmpeg
  +    graphviz
       gdk-pixbuf
       gexiv2
       glib
  
positive.code:     platforms;
  
    channel = "0.4";
    version = "${channel}.6";
  in
  stdenv.mkDerivation rec {
    name = "gegl-${version}";
  
    src = fetchurl {
      url = "https://download.gimp.org/pub/gegl/${channel}/${name}.tar.bz2";
      multihash = "QmPSjiRoCAUwrf42mUrjKDEXuy15a39xjy4z3zgbJA418e";
      hashOutput = false;
      sha256 = "f8cb45da736131fe29582b74cf6851102ae013bf99c77413a8bcb02e92e57890";
    };
  
    nativeBuildInputs = [
  
negative.code:   passthru = {
      srcVerification = fetchurl {
        failEarly = true;
        inherit (src)
          urls
          outputHash
          outputHashAlgo;
        fullOpts.sha256Urls = map (n: "${n}/../SHA256SUMS") src.urls;
      };
    };
  
  