anchor.diff: -{ SDL2
  +{ mkDerivation
  +, fetchFromGitHub
  +, SDL2
   , cmake
  -, fetchFromGitHub
  -, ffmpeg_3
  +, ffmpeg
   , glew
   , lib
   , libzip
  -, mkDerivation
   , pkg-config
   , python3
   , qtbase
  
positive.code:     repo = pname;
      rev = "v${version}";
      fetchSubmodules = true;
      sha256 = "19948jzqpclf8zfzp3k7s580xfjgqcyfwlcp7x7xj8h8lyypzymx";
    };
  
    postPatch = ''
  
negative.code: 
    buildInputs = [
      SDL2
      ffmpeg
      glew
      libzip
      qtbase
  