Prepare for FreeBSD 11 and 12.
Merge branch 'V5-5-patches' into V5-6-patches

* V5-5-patches:
  Prepare for FreeBSD 11 and 12.
Merge branch 'V5-4-patches' into V5-5-patches

* V5-4-patches:
  Prepare for FreeBSD 11 and 12.
Update to current IANA-ADDRESS-FAMILY-NUMBERS-MIB and current RFCs.
Use inet_pton onplace of inet_aton to help portability.
Prepare for FreeBSD 11 and 12
Prepare for FreeBSD 11 and 12
Merge branch 'V5-5-patches' into V5-6-patches

* V5-5-patches:
  Prepare for FreeBSD 11 and 12