Tweak linux_getifhwaddr

No functional change.
Fixed off-by-one in virtualhost processing. Previous code was checking if
Host header is a prefix of any existing vhost. This behaviour might be used to
uncover existing vitual hosts from the remote.

OK @mrg
Fixed memory leak in case of multiple authentication headers sent by the
client.

OK mrg@
Replace callout_stop with callout_halt

In order to call callout_destroy for a callout safely, we have to ensure
the function of the callout is not running and pending. To do so, we should
use callout_halt, not callout_stop.

In this case, we need to pass an interlock to callout_halt to wait for
the callout complete.

Reviewed by riastradh@.
kill the dropped privs info message
Expand pserialize(9) example to include publish, read, and destroy.
Bump date.
Fix typo: pserialize_read_exit(s), not s = pserialize_read_exit().
Elaborate comment before pserialize_perform.
Use membar_consumer until we have membar_datadep_consumer.
rename to bugstart.S
Add libkern for umoddi3 needed for correct leap yar computation in is_leap_year.
We don't need a special rule now that the file is called .S (having a
just .o rule before broke the MKDEBUG build).
Use proper index types, delete casts, use correct sizeof() in allocations.
Fix = -> == in conditional in example.  Oops!
Change internal temperature base from -267.7C to -243.7C. The AXP223
datasheet says that the value is between -267.7C and 165.8C in steps of 0.1C,
but this doesn't make sense for a 12-bit field. If we take the maximum value
and subtract 4095 we get -243.7C, effectively adding +24C to the reported
temp. On my A31 board, this changes a chilly 15.3C to a more reasonable 39.3C.
Explicitly compare to NULL to show clang that the bool conversion is
intentional, even if it is always true in case of the arrays.
Preserve const.
No reason not to make the string const.
Drop unnecessary-but-harmful casts.