anchor.diff:      description = "A video processing framework with the future in mind";
       homepage    = http://www.vapoursynth.com/;
       license     = licenses.lgpl21;
  -    platforms   = platforms.unix;
  +    platforms   = platforms.x86_64;
       maintainers = with maintainers; [ rnhmjoj ];
     };
   
  
positive.code: 
  stdenv.mkDerivation rec {
    name = "vapoursynth-${version}";
    version = "R40";
  
    src = fetchFromGitHub {
      owner  = "vapoursynth";
      repo   = "vapoursynth";
      rev    = version;
      sha256 = "1ycc3fdhhryp7hap80z3qmh89br31kcswzp8ai3wlc07zfvcrfck";
    };
  
    nativeBuildInputs = [ pkgconfig autoreconfHook nasm ];
  
negative.code: { stdenv, fetchFromGitHub, pkgconfig, autoreconfHook
  , zimg, libass, python3, libiconv
  , ApplicationServices, nasm
  , ocrSupport ?  false, tesseract ? null
  , imwriSupport? true,  imagemagick7 ? null
  }:
  
  assert ocrSupport   -> tesseract != null;
  