BUG: tc filter show ... produce a segmentation fault if more than one
filter rule with action -j MARK exists.

Reason: In print_ipt(...) xtables will be initialzed with a
pointer to the static struct tcipt_globals at xtables_init_all().
Later on the fields .opts and .options_offset of tcipt_globals are
modified. The call of xtables_free_opts(1) at the end of print(...)
does not restore the original values of tcipt_globals for the
modified fields. It only frees some allocated memory and sets
.opts to NULL. This leads to a segmentation fault when print_ipt()
is called for the next filter rule with action -j MARK.

Fix: Cloneing tcipt_globals on the stack as tmp_tcipt_globals and
use it instead of tcipt_globals, so tcipt_globals will be not
modified.
Signed-off-by: Andreas Greve <andreas.greve@a-greve.de>