anchor.diff:  { stdenv
  +, autoreconfHook
   , fetchurl
   , intltool
  +, lib
   
   , babl
   , cairo
   , exiv2
  -, ffmpeg
  -, gdk-pixbuf
  +, ffmpeg_2
  +, gdk-pixbuf_unwrapped
   , gexiv2
   , glib
   , gobject-introspection
  
positive.code:   ];
  
    configureFlags = [
      "--disable-docs"
      "--without-mrg"
      "--without-lensfun"
      "--without-sdl"
      "--without-graphviz"
      "--without-lua"
      "--without-libspiro"
      "--without-umfpack"
      "--without-libv4l"  # This is currently broken
    ];
  
    meta = with stdenv.lib; {
      description = "Graph-based image processing framework";
      homepage = http://www.gegl.org;
      license = licenses.gpl3;
      maintainers = with maintainers; [
        wkennington
      ];
      platforms = with platforms;
  
negative.code: , libwebp
  , openexr
  , pango
  , v4l_lib
  , vala
  }:
  
  let
    inherit (stdenv)
      targetSystem;
    inherit (lib)
      boolEn
      boolWt
      elem
      platforms;
  
    channel = "0.3";
    version = "${channel}.8";
  in
  stdenv.mkDerivation rec {
    name = "gegl-${version}";
  
    src = fetchurl {
      url = "https://download.gimp.org/pub/gegl/${channel}/${name}.tar.bz2";
      sha256 = "06ca9e67a59da026eb941b9d323269d7c19a922f1e478acdd3791a0eef8b229b";
    };
  
    nativeBuildInputs = [
      # Pre-generated autoconf/automake files are outdated and fail
      # to detect libv4l & ffmpeg correctly.
      autoreconfHook
      intltool
    ];
  
    buildInputs = [
      babl
      cairo
      #exiv2
      ffmpeg_2
      gdk-pixbuf_unwrapped
      #gexiv2
      glib
      gobject-introspection
      jasper
  