Fix Darwin stdenv to work on 10.13

The main changes are in libSystem, which lost the coretls component in 10.13
and some hardening changes that quietly crash any program that uses %n in
a non-constant format string, so we've needed to patch a lot of programs that
use gnulib.

pkgs/tools/compression/gzip/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, xz }:
+{ stdenv, hostPlatform, fetchurl, xz }:
 
 stdenv.mkDerivation rec {
   name = "gzip-${version}";
@@ -9,6 +9,8 @@ stdenv.mkDerivation rec {
     sha256 = "1lxv3p4iyx7833mlihkn5wfwmz4cys5nybwpz3dfawag8kn6f5zz";
   };
 
+  patches = stdenv.lib.optional hostPlatform.isDarwin stdenv.secure-format-patch;
+
   outputs = [ "out" "man" "info" ];
 
   enableParallelBuilding = true;