anchor.diff:    meta = with stdenv.lib; {
         description = "A free, open-source boardgame engine";
         homepage = "http://www.vassalengine.org/";
  -      license = licenses.lgpl21;
  +      license = licenses.lgpl21Only;
         maintainers = with maintainers; [ tvestelind ];
         platforms = platforms.linux;
     };
  
positive.code: { stdenv, fetchurl, jre, makeWrapper }:
  
  stdenv.mkDerivation rec {
    name = "VASSAL-3.3.2";
  
    src = fetchurl {
      url = "mirror://sourceforge/vassalengine/${name}-linux.tar.bz2";
      sha256 = "1abhlkl27gyfa1lghvv76xa6ks5hiwv2s9wb9ddadm0m07f87n1w";
    };
  
    buildInputs = [ makeWrapper ];
  
negative.code:   installPhase = ''
      mkdir -p $out/bin $out/share/vassal $out/doc
  
      cp CHANGES LICENSE README.md $out
      cp -R lib/* $out/share/vassal
      cp -R doc/* $out/doc
  
  