Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

This commit was generated by cvs2svn to compensate for changes in r98530,
which included commits to RCS files with non-trunk default branches.

Import libpcap 0.7.1, from
http://www.tcpdump.org/release/libpcap-0.7.1.tar.gz