firewall: link iptables extensions dynamically

firewall: link iptables extensions dynamically

Use shared libipt{,4,6}ext.so libraries instead of statically linking
the userspace matches into the fw3 executable.

As a side effect the match initialization is extremely simplified
compared to the weak function pointer juggling performed before.

This also fixes the initialization of the multiport match.

Signed-off-by: Jo-Philipp Wich <[email protected]>
SVN-Revision: 45764