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