{stdenv, fetchurl, readline}: stdenv.mkDerivation {
  name = "which-2.20";
  src = fetchurl {
    url = mirror://gnu/which/which-2.20.tar.gz;
    sha256 = "1y2p50zadb36izzh2zw4dm5hvdiydqf3qa88l8kav20dcmfbc5yl";
  };

  buildInputs = [readline];
}