anchor.diff:      ladspaPlugins
     ];
   
  -  nativeBuildInputs = [ which ];
  +  nativeBuildInputs = [ cmake which ];
   
     outputs = [ "out" "dev" ];
  -
  -  # Mostly taken from:
  -  # http://www.kdenlive.org/user-manual/downloading-and-installing-kdenlive/installing-source/installing-mlt-rendering-engine
  -  configureFlags = [
  -    "--avformat-swscale"
  -    "--enable-gpl"
  -    "--enable-gpl3"
  -    "--enable-opengl"
  -  ];
  -
  -  # mlt is unable to cope with our multi-prefix Qt build
  -  # because it does not use CMake or qmake.
  -  NIX_CFLAGS_COMPILE = "-I${getDev qtsvg}/include/QtSvg";
  -
  -  CXXFLAGS = "-std=c++11";
   
     qtWrapperArgs = [
       "--prefix FREI0R_PATH : ${frei0r}/lib/frei0r-1"
       "--prefix LADSPA_PATH : ${ladspaPlugins}/lib/ladspa"
     ];
  -
  -  postInstall = ''
  -    # Remove an unnecessary reference to movit.dev.
  -    s=${movit.dev}/include
  -    t=$(for ((i = 0; i < ''${#s}; i++)); do echo -n X; done)
  -    sed -i $out/lib/mlt/libmltopengl.so -e "s|$s|$t|g"
  -
  -    # Remove an unnecessary reference to movit.dev.
  -    s=${qtbase.dev}/include
  -    t=$(for ((i = 0; i < ''${#s}; i++)); do echo -n X; done)
  -    sed -i $out/lib/mlt/libmltqt.so -e "s|$s|$t|g"
  -  '';
   
     passthru = {
       inherit ffmpeg;
  
positive.code: let inherit (lib) getDev; in
  mkDerivation rec {
    pname = "mlt";
    version = "6.24.0";
  
    src = fetchFromGitHub {
      owner = "mltframework";
      repo = "mlt";
      rev = "v${version}";
      sha256 = "1my43ica2qax2622307dv4gn3w8hkchy643i9pq8r9yh2hd4pvs9";
    };
  
    buildInputs = [
  
negative.code: { lib
  , fetchFromGitHub
  , cmake
  , SDL
  , ffmpeg
  , frei0r
  