MFC r257037: Redefine the io provider using the SDT(9) macros

MFC slacker:	markj
MFC r250817: Use SDT_PROBE1() instead of SDT_PROBE()

MFC slacker:	pjd
MFC r251237: Port the SDT test
MFC r227294: SDT's struct sdt_argtype can be marked static everywhere

MFC slacker:	ed
followup to r260816, MFC of r257037: remove dtio from dtrace Makefile

svn merge ran without any complains or errors, but this Makefile somehow
was not updated.

This is a direct commit.

Reported by:	Jukka Ukkonen <jau789@gmail.com>
MFC of 260088:

Fine tune filesystem block allocations under low free-space
conditions (-r254995) based on further operational experience.

Submitted by:  Dmitry Sivachenko
Fix Tested by: Dmitry Sivachenko
MFC r260566: Remove incorrect bit shift when assigning the LUN request field
MFC r250816:

Protect SDT_PROBE() with do { } while (0) loop.
MFC r245848 (by jhb):
Always update the hw.uart.console hint anytime a change is made to the
comconsole setup.  Previously the hint would be set when if you set a
custom port, but it would not be updated if you later set a custom speed.

Also, leave the hw.uart.console hint mutable so it can be overridden or
unset by the user if needed.
MFC r251223 (by nyan):
Always update the hw.uart.console hint.
MFC r255077:

acpi_thermal: Warn about insane _TMP temperature only once

A warning is emitted again if the temperature became briefly valid
meanwhile. This avoids spamming the user when the sensor is broken.

Other values (ie. not _TMP) always raise a warning.
MFC r259729:
  Bootstrap etcupdate(8) as part of the release build, similar
  to what is done for mergemaster(8).  This allows etcupdate(8)
  to work out-of-box after the first upgrade of a system.

Sponsored by:	The FreeBSD Foundation
MFH: r260483, r260484, r260594, r260595, r260596, r260597

Improve error message shown to the user when trying to load a module that is
already loaded or compiled withing the kernel
Point the user to dmesg(1) to get informations about why loading a module did fail
instead of printing the cryptic "Exec format error"
Update the BUGS section of kld(4) according the recent changes in kldload(8)
MFC	r260014, r260099:

gcc: Add support for label attributes and "unavailable" attribute.

Apple GCC has extensions to support for both label attributes and
an "unavailable" attribute. These are critical for objc but are
also useful in regular C/C++.

Obtained from:	Apple GCC 4.2 - 5531
MFC r260833:

Bring back r226403, the fix for bin/161526, which was (accidentally?)
reverted in r238896.

PR:		bin/161526
Reported by:	Karli.Sjoberg slu.se
MFC	r260332;
gcc: backport some fixes from llvm-gcc

llvm-gcc backported some patches from gcc trunk:

http://gcc.gnu.org/ml/gcc-cvs/2007-05/msg00662.html
http://gcc.gnu.org/ml/gcc-cvs/2007-07/msg00019.html
http://gcc.gnu.org/ml/gcc-cvs/2007-08/msg00240.html
http://gcc.gnu.org/ml/gcc-cvs/2007-08/msg00493.html

The first two were always GPL2. The last two were
added after the GPL3 transition, but were written
by aaw@google.com and Rafael Espíndola got permission
to relicense them under the GPL2 for inclusion in
llvm-gcc.

This fixes GCC-PR c++/31749

Obtained from:	llvm-gcc (rev. 75463; GPLv2)
MFC r260782:

-h and -H options backwards in manual page.
MFC r254970 (by ken):
If a drive returns ASC/ASCQ 0x04,0x11 "Logical unit not ready,
notify (enable spinup) required", instead of doing the normal
retries, poll for a change in status.

We will poll every half second for a minute for the status to
change.

Hitachi drives (and likely other SAS drives) return that ASC/ASCQ
when they are waiting to spin up.  What it means is that they are
waiting for the SAS expander to send them the SAS
NOTIFY (ENABLE SPINUP) primitive.

That primitive is the mechanism expanders/enclosures use to
sequence drive spinup to avoid overloading power supplies.
MFC r255307 (by bryanv):
Add camcontrol support for the SCSI sanitize command
MFC r256836:
Remove hard limit on number of BIOs handled with one ATA TRIM request.