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

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

Reduce the memory requirements for the tables by (1) using malloced strings
instead of maximum sized arrays embedded in the table structures and (2)
using pointers to constant oids instead of copying the oid into each
table structure. This also fixes indexing in the case when a string used
for indexing is longer than the maximum size allowed in the MIB.

Submitted by: Victor Cruceru <soc-victor@>

Forced commit because I lost the commit message in the previous commit:

This is the implementation of the HOSTRES MIB that was developed by
Victor during SoC 2005 with some stylification by philip@ and harti@.

Submitted by: Victor Cruceru <soc-victor@freebsd.org>
Reviewed by: philip, harti

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