anchor.diff: -{ fetchurl, stdenv }:
  +{ fetchurl, stdenv, gmp }:
   
   stdenv.mkDerivation rec {
     name = "bigloo-${version}";
  -  version = "3.7a";
  +  version = "4.1a-2";
   
     src = fetchurl {
       url = "ftp://ftp-sop.inria.fr/indes/fp/Bigloo/bigloo${version}.tar.gz";
  -    sha256 = "0y8i87c2bpqzap8rhzgpyfgdzq21py5xq6mgp0w6xv4rjcj9d0v1";
  +    sha256 = "09yrz8r0jpj7bda39fdxzrrdyhi851nlfajsyf0b6jxanz6ygcjx";
     };
  +
  +  buildInputs = [ gmp ];
   
     preConfigure =
       # Help libgc's configure.
  
positive.code:       Scheme and C programs, between Scheme and Java programs, and
        between Scheme and C# programs.
      '';
  
      homepage = http://www-sop.inria.fr/indes/fp/Bigloo/;
      license = stdenv.lib.licenses.gpl2Plus;
  
      maintainers = [ stdenv.lib.maintainers.ludo ];
      platforms = stdenv.lib.platforms.gnu;  # arbitrary choice
    };
  }
  
negative.code: 
    meta = {
      description = "Efficient Scheme compiler";
      homepage    = http://www-sop.inria.fr/indes/fp/Bigloo/;
      license     = stdenv.lib.licenses.gpl2Plus;
      platforms   = stdenv.lib.platforms.unix;
      maintainers = with stdenv.lib.maintainers; [ ludo thoughtpolice ];
  
      longDescription = ''
        Bigloo is a Scheme implementation devoted to one goal: enabling
  