anchor.diff:  
       pak128 = {
         srcPath = "pak128%20for%20ST%20120.2.2%20%282.7%2C%20minor%20changes%29/pak128";
  -      sha256 = "1x6g6yfv1hvjyh3ciccly1i2k2n2b63dw694gdg4j90a543rmclg";
  +      sha256 = "0z01y7r0rz7q79vr17bbnkgcbjjrimphy1dwb1pgbiv4klz7j5xw";
       };
       "pak128.britain" = {
         srcPath = "pak128.Britain%20for%20120-1/pak128.Britain.1.17-120-1";
  
positive.code: 
      sourceRoot = ".";
  
    nativeBuildInputs = [ pkgconfig ];
      buildInputs = [ zlib libpng bzip2 SDL SDL_mixer unzip ];
  
      configurePhase = let
  
negative.code:   );
  
    ver1 = "120";
    ver2 = "4";
    ver3 = "1";
    version =   "${ver1}.${ver2}.${ver3}";
    ver_dash =  "${ver1}-${ver2}-${ver3}";
  
    binary_src = fetchurl {
      url = "mirror://sourceforge/simutrans/simutrans/${ver_dash}/simutrans-src-${ver_dash}.zip";
      sha256 = "0yw7vjvmczp022mgk35swwhpbiszpz91mwsgicxglwivgc30vvic";
    };
  
  
  