bsnmpd(8): fix and optimize interface description processing

* correctly prepare a buffer to obtain interface description from a kernel and
truncate long description instead of dropping it altogether and
spamming logs;
* skip calling strlen() for each description and each SNMP request
for MIB-II/ifXTable's ifAlias.
* teach bsnmpd to allocate memory dynamically for interface descriptions
to decrease memory usage for common case and not to break
if long description occurs;

PR: 217763
Reviewed by: harti and others
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D16459

style(9): clean up trailing whitespace

MFC after: 3 weeks

Change the variable to a #define in order to make gcc happy which
otherwise will complain about "variably modified 'alias' at file scope".
Unbreaks the build on gcc platforms.

Fill the ifAlias leaf of the ifXTable with the interface description
if there is one available and it fits into the maximum size (64 characters).

fix build

MFC after: 1 week

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

MFC r200063

Fix a problem with high CPU consumption (up to 30%) by bsnmpd on a loaded system.
Instead of constantly calling the mibII_idle function when the server is not busy
call the function only once every 10 seconds to avoid bsnmpd constantly doing
gettimeofday syscalls. Make the idle polling interval confugurable via
begemotIfDataPoll.

Fix a problem with high CPU consumption (up to 30%) by bsnmpd on a loaded system.
Instead of constantly calling the mibII_idle function when the server is not busy
call the function only once every 10 seconds to avoid bsnmpd constantly doing
gettimeofday syscalls. Make the idle polling interval confugurable via
begemotIfDataPoll.

Reported and tested by: misho (at) aitbg (dot) com
Oked by: harti
MFC after: 1 week

- Import the HEAD csup code which is the basis for the cvsmode work.

Virgin import of bsnmpd 1.12

Vendor fix: make mibII HC counters really 64-bit on 32-bit platforms by polling
the kernel periodically.

Submitted by: glebius (partly)

Virgin import of bsnmpd 1.11

Virgin import of bsnmpd 1.10

Virgin import of bsnmpd 1.7

Virgin import of bsnmpd 1.5a

Virgin import of bsnmp 1.4