Fix libpcap issue #893: check for invalid IPv4 addresses.
This fixes errors such as:
tcpdump -i lagg0 net 999.999.999.999
This was originally discovered on a Red Hat 7.7 server and verified
to also be a bug on FreeBSD.
Submitted by: cy
Reported by: cy
Approved by: garga (maintainer)
Obtained from: https://github.com/the-tcpdump-group/libpcap/commit/ \
Fixed by: https://github.com/guyharris