MFC r310092:

Add a free_iovec() function to reset iovec's.

The primary purpose is to call nmount() in a loop with new iovec's so
free_iovec takes arguments by reference and resets their values.

Reviewed by: cem
MFC after: 1 week
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D8513

MFC r270096:

Bring in the new automounter, similar to what's provided in most other
UNIX systems, eg. MacOS X and Solaris. It uses Sun-compatible map format,
has proper kernel support, and LDAP integration.

There are still a few outstanding problems; they will be fixed shortly.

Reviewed by: allanjude@, emaste@, kib@, wblock@ (earlier versions)
Phabric: D523
Relnotes: yes
Sponsored by: The FreeBSD Foundation

MFC r270096:

Bring in the new automounter, similar to what's provided in most other
UNIX systems, eg. MacOS X and Solaris. It uses Sun-compatible map format,
has proper kernel support, and LDAP integration.

There are still a few outstanding problems; they will be fixed shortly.

Reviewed by: allanjude@, emaste@, kib@, wblock@ (earlier versions)
Phabric: D523
Relnotes: yes
Sponsored by: The FreeBSD Foundation