anchor.diff:    inherit name;
   
     src = fetchurl {
  -      url = https://gforge.inria.fr/frs/download.php/22124/ecm-6.2.3.tar.gz;
  -      sha256 = "1iwwhbz5vwl7j6dyh292hahc8yy16pq9mmm7mxy49zhxd81vy08p";
  +      url = http://gforge.inria.fr/frs/download.php/file/32159/ecm-6.4.4.tar.gz;
  +      sha256 = "0v5h2nicz9yx78c2d72plbhi30iq4nxbvphja1s9501db4aah4y8";
       };
   
  -  buildInputs = [ gmp ];
  +  buildInputs = [ m4 gmp ];
   
     doCheck = true;
   
  
positive.code:     license = stdenv.lib.licenses.gpl2Plus;
      homepage = http://ecm.gforge.inria.fr/;
      maintainers = [ stdenv.lib.maintainers.roconnor ];
    };
  }
  
negative.code: { stdenv, fetchurl, gmp, m4 }:
  
  let
    pname = "ecm";
    version = "6.4.4";
    name = "${pname}-${version}";
  in
  
  