build: fail in configure on missing dependency with --enable-bpf-compiler

The build of utils/nfbpf_compile depends on libpcap. If configure is
run with --enable-bpf-compiler, the script succeeds, but make fails.

This small patch adds a test for the dependency (libpcap) in configure
and fails hard if not found.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
iptables: iptables-xml: Fix various parsing bugs

There are two bugs in iptables-xml do_rule_part parsing corrected by this patch:

1) Ignore "-A <chain>" instead of just "-A"
2) When checking to see if we need a <match> tag, inversion needs to be taken
   into account

This closes netfilter bugzilla #679.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
iptables-xml: fix parameter parsing (similar to 2165f38)

Similar to (2165f38 iptables-restore: fix parameter parsing
(shows up with gcc-4.7)), make sure iptables-xml doesn't hit
the same problem.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>