Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Several cleanups to ipfwpcap(8).

- Enable WARNS?=6.
- Include missing headers.
- Mark prog and pidfile as static. Remove unneeded initializer.
- Use ANSI prototypes.
- Remove unneeded fp variable.
- snprintf() guarantees the buffer to be null terminated. Remove
unneeded - 1 and bzero call.
- Remove unneeded casting.

Submitted by: Pawel Worach, Christoph Mallon

Add a signal handler for SIGINT to make sure that the PID file
gets cleaned up upon receiving SIGINT. This un-breaks subsequent
executions of ipfwpcap and helps when debugging network/divert
issues like this:

ipfwpcap -r 6000 - | tcpdump -r -

MFC after: 1 week

add define's from config.h for pcap-int.h; this is a noop now
but will be required for libpcap 0.9.4

Add a small tool which captures packets on a DIVERT socket and writes
them as pcap (tcpdump) format data to a file or pipe.

Volunters wanted for: manpage
Contributed by: P Kern <pkern@cns.utoronto.ca>