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

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

Include stdint.h to fix build.

Pointed by: Olivier Cochard-Labbé

Prepare network statistics structures for migration to PCPU counters.
Use uint64_t as type for all fields of structures.

Changed structures: ahstat, arpstat, espstat, icmp6_ifstat, icmp6stat,
in6_ifstat, ip6stat, ipcompstat, ipipstat, ipsecstat, mrt6stat, mrtstat,
pfkeystat, pim6stat, pimstat, rip6stat, udpstat.

Discussed with: arch@

Update structure name to follow the new IPsec code.

Reported by: phk
Approved by: re

o add missing copyright notices
o new hifnstats program to dump hifn driver statistics
o new ipsecstats program to dump fast ipsec statistics