ex.nix

stdenv.mkDerivation rec {
  name = "emacs-24.5";

  builder = ./builder.sh;

  src = verifysignature {
    src = fetchurl {
      url = "mirror://gnu//emacs/${name}.tar.xz";
      sha256 = "0kn3rzm91qiswi0cql89kbv6mqn27rwsyjfb8xmwy9m5s8fxfiyx";
    };
    signature = fetchurl {
      url = "mirror://gnu//emacs/${name}.tar.xz.sig";
      sha256 = "04fcwm3j365ar278gfbyxcxbh5fn1l93pg0mpdj7vqr1r1cqbi6k";
    };
    keys = keyset {
      fingerprints = [
        "28D3 BED8 51FD F3AB 57FE F93C 2335 87A4 7C20 7910"
      ];
      sha256 = "118k6z02qp08xxw1srn33kdqwnc0i7xwrimvz3fqw9y2iwy9c4xg";
    };
  };