from Brad; I've read and tested it, also reads ok to dlg@.

- Further simplify the re(4) receive filter handling and
  have everything taken care of in re_iff(), eliminating
  a bit of code from re_init().
- Remove unused if_flags field.
Lift the NFS over UDP retransmit logic from FreeBSD.

OK blambert@

FreeBSD commit message:
Refactor the NFS over UDP retransmit timeout estimation logic to allow
the estimator to be more easily tuned and maintained.

There should be no functional change except there is now a lower limit
on the retransmit timeout to prevent the client from retransmitting
faster than the server's disks can fill requests, and an upper limit
to prevent the estimator from taking to long to retransmit during a
server outage.
Added ejectable bay for IDE cdroms
ok marco@
jordan and marco claim this is about to work, so stop spreading dread
Only need to umount once on restarting. Force umounts in case of
restarting. No need to ask for verbose umount output since we send
it all to /dev/null. Make sure we start in '/', lest we were restarted
while exploring the installed/upgraded filesystems.
Add acpivideo support. This adds brightness support for all laptops
except thinkpads, they will use the acpithinkpad driver. The driver is
also hooked into wsconsole. So brightness can be adjusted via:

$ wsconsctl display.brightness=<percentage>

This is very helpfull on some laptops that have a nasty bios and get two
steps instead of one when pressing the brightness button.

Tested on various dell, fujitsu, acer, samsung and other laptops.

Okay marco@, miod@. Suggestions from kettenis@.
Lots of reviews and help from miod@, thanks!
Nuke CYRIX_CACHE (and related defines).  They've not been used in a long
time.  Beginning of refactoring cpu identification.

ok kettenis@
Synchronize man page and help output.
From a least of details by sobrado@; input by jmc@ who still isn't happy.
Just like on amd64. Instead of keeping a bitmap of which cpus a pmap
is active on, save a curpmap pointer in cpu_info. This lets us simplify
a few things and do lazy context switching from a user process to a
kernel thread. There's a new IPI introduced for forcing a cr3 reload
when we're tearing down a dead pmap.

kettenis@ ok (after I polished a few minor things)
remove unneeded ARGSUSED; ok krw@ henning@
remove cruft that snuck in with previous
droppmap is only necessary (and declared) on MULTIPROCESSOR
Make sure we don't stomp on a RAID partition that is already in use.
Code is now enabled and ready for general testing.
More KNF
ok marco@
Remove some redundant code.
remove the never used bufq_ code.

ok oga@
'dance for me' blambert@
Don't postpone memory allocation for the error message to the error handler:
That way, memory exhaustion simply cannot be reported because it would
require to...  allocate memory.
Instead, really use a statical buffer as it is advertised in the manual.
"looks good" millert@
sync
kill some unused defines, don't do an ifndef dance for
things that should be defined here and remove a silly
comment.
Revert readv/writev changes, as they trigger an apparent file descriptor
deadlock for ckuethe@

"if you have to revert, you have to revert" deraadt@