anchor.diff:  { stdenv, fetchurl, bison, flex, gettext, pkgconfig, libpng
   , libtheora, openal, physfs, mesa, fribidi, fontconfig
   , freetype, qt4, glew, libogg, libvorbis, zlib, libX11
  -, libXrandr, zip, unzip, which
  +, libXrandr, zip, unzip, which, perl
   , withVideos ? false
   }:
  -stdenv.mkDerivation rec {
  +
  +let
     pname = "warzone2100";
  -  version = "3.1.1";
  -  name = "${pname}-${version}";
  -  src = fetchurl {
  -    url = "mirror://sourceforge/${pname}/releases/${version}/${name}.tar.xz";
  -    sha256 = "c937a2e2c7afdad00b00767636234bbec4d8b18efb008073445439d32edb76cf";
  -  };
     sequences_src = fetchurl {
       url = "mirror://sourceforge/${pname}/warzone2100/Videos/high-quality-en/sequences.wz";
       sha256 = "90ff552ca4a70e2537e027e22c5098ea4ed1bc11bb7fc94138c6c941a73d29fa";
     };
  +in
  +
  +stdenv.mkDerivation rec {
  +  version = "3.1.5";
  +  name = "${pname}-${version}";
  +  src = fetchurl {
  +    url = "mirror://sourceforge/${pname}/releases/${version}/${name}.tar.xz";
  +    sha256 = "0hm49i2knvvg3wlnryv7h4m84s3qa7jfyym5yy6365sx8wzcrai1";
  +  };
     buildInputs = [ bison flex gettext pkgconfig libpng libtheora openal
                     physfs mesa fribidi fontconfig freetype qt4
                     glew libogg libvorbis zlib libX11 libXrandr zip
  -                  unzip
  +                  unzip perl
                   ];
     patchPhase = ''
       substituteInPlace lib/exceptionhandler/dumpinfo.cpp \
  
positive.code: 
    NIX_CFLAGS_COMPILE = "-fpermissive"; # GL header minor incompatibility
  
    postInstall = []
      ++ stdenv.lib.optional withVideos "cp ${sequences_src} $out/share/warzone2100/sequences.wz";
  
    meta = with stdenv.lib; {
      description = "A free RTS game, originally developed by Pumpkin Studios";
  
negative.code:       missiles. The game offers campaign, multi-player, and single-player
        skirmish modes. An extensive tech tree with over 400 different
        technologies, combined with the unit design system, allows for a wide
        variety of possible units and tactics.
      '';
      homepage = http://wz2100.net;
      license = licenses.gpl2Plus;
  