multipath-tools: ensure gzip does not capture timestamp

gzip is originally called as 'gzip -9 -c'

This is a port of
a8e7ddd1df

Note that it does not seem to make a difference to `nix-build --check`.

pkgs/os-specific/linux/multipath-tools/default.nix

@@ -15,6 +15,8 @@ stdenv.mkDerivation rec {
     ' libmultipath/defaults.h
     sed -i -e 's,\$(DESTDIR)/\(usr/\)\?,$(prefix)/,g' \
       kpartx/Makefile libmpathpersist/Makefile
+    sed -i -e "s,GZIP = .*, GZIP = gzip -9n -c," \
+      Makefile.inc
   '';
 
   nativeBuildInputs = [ gzip ];