Import new version of libcxxrt.

Approved by:	dim (mentor)
Import new version of libcxxrt to vendor branch.

Approved by:	dim (mentor)
Fix !INVARIANTS && !SMP build.

MFC after:	3 days
MFV: one-true-awk 20121220.

MFC after:	1 month
Temporarily revert rev 244678.  This is causing loopback problems with
the lo (loopback) interfaces.
- Fix !SMP build.
- Replace incorrect function names in printf(9) strings with __func__.
- Make xctrl_shutdown_reasons table const.
- Use nitems() rather than rolling an own version.
- Use DEVMETHOD_END.
- Use NULL rather than 0 for pointers.

MFC after:	3 days
- Replace partially incorrect function names in panic(9) strings with
  __func__ and add some missing ones.
- Remove a stale comment.
- Remove unused NUM_ELEMENTS macro.
- Remove extra empty lines.
- Use DEVMETHOD_END.
- Use NULL rather than 0 for pointers.

MFC after:	3 days
As discussed on -current last October, remove the firewire drivers from
GENERIC.
Remove files not connected to the build. It's confusing enough that
we still have two not quite the same evtchn.c left over.

MFC after:	3 day
Comments.
Fix a typo in an error message.

Approved by:	rstone (co-mentor)
MFC after:	1 week
Have -n imply -r, since dry-run mode obviously doesn't require root
privileges.

Approved by:	rstone (co-mentor)
MFC after:	1 week
Make sure to update the mtime of a logfile after archiving it. This
ensures that the next rotation happens at the correct time when using
interval-based rotations.

PR:		bin/174438
Reviewed by:	gad
Approved by:	rstone (co-mentor)
MFC after:	1 week
Tone down the encouragement to use cvsup.  Add directions to the handbook
pages that cover the more current methods and bring closer to reality.
Remove the last use of the deprecated MNT_VNODE_FOREACH interface in
the tree.

With the help from:	mjg
Tested by:	Ronald Klop <ronald-freebsd8@klop.yi.org>
MFC after:	2 weeks
Remove the deprecated MNT_VNODE_FOREACH interface.  Use the
MNT_VNODE_FOREACH_ALL instead.
Don't call the spectral methods for NICS that don't implement them.
Enable the UFS quotas for big-iron GENERIC kernels.

Discussed with:	      mckusick
MFC after:	      2 weeks
Add the "nocache" nullfs mount option, which disables the caching of
the free nullfs vnodes, switching nullfs behaviour to pre-r240285.
The option is mostly intended as the last-resort when higher pressure
on the vnode cache due to doubling of the vnode counts is not
desirable.

Note that disabling the cache costs more than 2x wall time in the
metadata-hungry scenarious.  The default is "cache".

Tested and benchmarked by:	pho (previous version)
MFC after:	2 weeks
Allow to specify "cache" and "nocache" as an option for
mount_nullfs(8).

Tested by:	pho
MFC after:	2 weeks