anchor.diff:        ("-" + target.config);
   
     src = fetchurl {
  -    url = "mirror://gnu/gdb/${basename}.tar.bz2";
  -    sha256 = "08vcb97j1b7vxwq6088wb6s3g3bm8iwikd922y0xsgbbxv3d2104";
  +    url = "mirror://gnu/gdb/${basename}.tar.xz";
  +    sha256 = "49c4abe174f79f54e1f9e75210ffb590d9b497d5b5200b5398c0e073a4ecb875";
     };
   
     patches = [ ./edit-signals.patch ];
  
positive.code:   nativeBuildInputs = [ texinfo python ]
      ++ stdenv.lib.optional isGNU mig;
  
    buildInputs = [ ncurses readline gmp mpfr expat ]
      ++ stdenv.lib.optional isGNU hurd
      ++ stdenv.lib.optional doCheck dejagnu;
  
  
negative.code: { fetchurl, stdenv, ncurses, readline, gmp, mpfr, expat, texinfo
  , dejagnu, python, pkgconfig, guile, target ? null
  
  # Additional dependencies for GNU/Hurd.
  , mig ? null, hurd ? null
  