anchor.diff: -{ stdenv, fetchurl, pythonPackages, pkgconfig, SDL
  +{ stdenv, fetchurl, pythonPackages, pkgconfig, SDL2
   , libpng, ffmpeg, freetype, glew, mesa, fribidi, zlib
  +, glib
   }:
   
   with pythonPackages;
   
   stdenv.mkDerivation {
  -  name = "renpy-6.17.6";
  +  name = "renpy-6.99.12.4";
   
     meta = {
       description = "Ren'Py Visual Novel Engine";
  
positive.code:     cp -r renpy renpy.py $out/share/renpy
      python module/setup.py install --prefix=$out --install-lib=$out/share/renpy/module
  
      wrapPythonPrograms
      makeWrapper ${python}/bin/python $out/bin/renpy \
        --set PYTHONPATH $program_PYTHONPATH \
        --set RENPY_BASE $out/share/renpy \
        --add-flags "-O $out/share/renpy/renpy.py"
    '';
  
    NIX_CFLAGS_COMPILE = "-I${pygame}/include/${python.libPrefix}";
  }
  
negative.code:   };
  
    src = fetchurl {
      url = "http://www.renpy.org/dl/6.99.12.4/renpy-6.99.12.4-source.tar.bz2";
      sha256 = "035342rr39zp7krp08z0xhcl73gqbqyilshgmljq0ynfrxxckn35";
    };
  
    buildInputs = [
      python cython pkgconfig wrapPython
      SDL2 libpng ffmpeg freetype glew mesa fribidi zlib pygame_sdl2 glib
    ];
  
    pythonPath = [ pygame_sdl2 ];
  
    RENPY_DEPS_INSTALL = stdenv.lib.concatStringsSep "::" (map (path: "${path}") [
      SDL2 SDL2.dev libpng ffmpeg ffmpeg.out freetype glew.dev glew.out mesa fribidi zlib
    ]);
  
    buildPhase = ''
  