multipath-tools: ensure gzip does not capture timestamp

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

This is a port of
https://github.com/NixOS/nixpkgs/pull/2281/commits/a8e7ddd1dfaae4b3ce97fdefe4614a3e31c04501

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

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

···
     ' 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 ];