anchor.diff:    patches =
       [ (fetchurl {
           url = http://rmdir.de/~michael/micropolis_git.patch;
  -        sha256 = "13419a4394242cd11d5cabd8b1b50787282ea16b55fdcfbeadf8505af46b0592";
  +        sha256 = "0sjl61av7lab3a5vif1jpyicmdb2igvqq6nwaw0s3agg6dh69v1d";
         })
       ];
   
  
positive.code:       chmod 755 $out/bin/micropolis
      '';
  
    meta = { 
      description = "GPL'ed version of S*m C*ty";
      homepage = http://www.donhopkins.com/home/micropolis/;
      license = "GPL";
  
negative.code: { stdenv, fetchurl, libX11, libXpm, libXext, xextproto, byacc }:
  
  stdenv.mkDerivation {
    name = "micropolis-2010-12-18"; # version from the patch timestamp
  
    src = fetchurl {
      url = http://www.donhopkins.com/home/micropolis/micropolis-activity-source.tgz;
  