anchor.diff:  
     postInstall = ''
       wrapProgram "$out/bin/spring" \
  -      --prefix LD_LIBRARY_PATH : "${stdenv.gcc.gcc}/lib64:${stdenv.gcc.gcc}/lib"
  +      --prefix LD_LIBRARY_PATH : "${stdenv.gcc.gcc}/lib64:${stdenv.gcc.gcc}/lib::${systemd}/lib"
     '';
   
     meta = with stdenv.lib; {
  
positive.code: { stdenv, fetchurl, cmake, lzma, boost, libdevil, zlib, p7zip
  , openal, libvorbis, glew, freetype, xlibs, SDL, mesa, binutils
  , asciidoc, libxslt, docbook_xsl, docbook_xsl_ns, curl, makeWrapper
  , jdk ? null, python ? null
  , withAI ? true # support for AI Interfaces and Skirmish AIs
  }:
  
  
negative.code: 
    buildInputs = [ cmake lzma boost libdevil zlib p7zip openal libvorbis freetype SDL 
      xlibs.libX11 xlibs.libXcursor mesa glew asciidoc libxslt docbook_xsl curl makeWrapper
      docbook_xsl_ns systemd ]
      ++ stdenv.lib.optional withAI jdk
      ++ stdenv.lib.optional withAI python;
  
  