anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "packmol";
  -  version = "20.2.2";
  +  version = "20.2.3";
   
     buildInputs = [ gfortran ];
   
  
positive.code:     owner = "m3g";
      repo = pname;
      rev = "v${version}";
      sha256= "0pj6ah09zbj3lir628p8rbfbkq4wqnmvcyvq3rqgbc7w2vyslxrk";
    };
  
    dontConfigure = true;
  
negative.code:     homepage = "http://m3g.iqm.unicamp.br/packmol/home.shtml";
      license = licenses.mit;
      platforms = platforms.linux;
      maintainers = [ maintainers.sheepforce ];
    };
  }
  