anchor.diff:  
     buildInputs = [ libpng libGLU_combined freeglut libX11 plib openal freealut libXrandr xorgproto
       libXext libSM libICE libXi libXt libXrender libXxf86vm zlib bash expat
  -    SDL2 enet libjpeg openscenegraph libvorbis ];
  +    SDL2 enet libjpeg openscenegraph libvorbis curl ];
   
     meta = {
       description = "Car racing game - TORCS fork with more experimental approach";
  -    homepage = http://speed-dreams.sourceforge.net/;
  +    homepage = "http://speed-dreams.sourceforge.net/";
       license = stdenv.lib.licenses.gpl2Plus;
       maintainers = with stdenv.lib.maintainers; [raskin];
       platforms = stdenv.lib.platforms.linux;
  
positive.code: { fetchurl, stdenv, libGLU_combined, freeglut, libX11, plib, openal, freealut, libXrandr, xorgproto,
  libXext, libSM, libICE, libXi, libXt, libXrender, libXxf86vm, openscenegraph, expat,
  libpng, zlib, bash, SDL2, enet, libjpeg, cmake, pkgconfig, libvorbis, runtimeShell }:
  
  stdenv.mkDerivation rec {
    version = "2.2.1-r6404";
    name = "speed-dreams-${version}";
  
    src = fetchurl {
      url = "mirror://sourceforge/speed-dreams/2.2.1/speed-dreams-src-base-${version}.tar.xz";
      sha256 = "0347sk8xbdsyvl48qybbycd7hvzsx5b37zzjx1yx73nzddhmlpbx";
    };
  
    cars-and-tracks = fetchurl {
      url = "mirror://sourceforge/speed-dreams/2.2.1/speed-dreams-src-hq-cars-and-tracks-${version}.tar.xz";
      sha256 = "1h50l110n42nrq6j3kcyhi3swgmrjcg979vb6h0zsf46afwv0z3q";
    };
  
    more-cars-and-tracks = fetchurl {
      url = "mirror://sourceforge/speed-dreams/2.2.1/speed-dreams-src-more-hq-cars-and-tracks-${version}.tar.xz";
      sha256 = "03m3gwd03jqgsfjdglzmrv613cp4gh50i63fwmnwl282zhxydcwd";
    };
  
    wip-cars-and-tracks = fetchurl {
      url = "mirror://sourceforge/speed-dreams/2.2.1/speed-dreams-src-wip-cars-and-tracks-${version}.tar.xz";
      sha256 = "0ysk756rd294xzpwvmjh0mb229ngzrc4ry9lpyhyak98rbcp9hxm";
    };
  
    sourceRoot = ".";
  
negative.code:     tar -xf ${cars-and-tracks}
      tar -xf ${more-cars-and-tracks}
      tar -xf ${wip-cars-and-tracks}
    '';
  
    preBuild = ''
  