Remove only-works-on-amd64 restriction.

Sponsored by:	The FreeBSD Foundation
Add ZEDBOARD.

Tested against:	stable/10@r262905 (build only)
Sponsored by:	The FreeBSD Foundation
Merge remote-tracking branch 'upstream/master'

Conflicts:
	bin/ls/ls.1
	sys/boot/amd64/efi/Makefile
Don't call sdhci_init_slot() until after handling the FDT properties
related to detecting card presence.  This actually makes no difference
now, but will when we get support for gpio-based card detection.
Change NO_EVENTTIMERS from an arm-specific to an MI option, so that it can
be used in MI code.

This is intended as a temporary measure to unbreak the build.  The real fix
is to write event timer drivers for legacy arm hardware, then get rid of
this option completely.  That's going to take a few days.
Add support for the virtio RNG entropy-source device.
Call through to /dev/random synchronously to fill
virtio buffers with RNG data.

Tested with FreeBSD-CURRENT and Ubuntu guests.

Submitted by:	Leon Dang
Discussed with:	markm
MFC after:	3 weeks
Sponsored by:	Nahanni Systems
Switch imx6 to using the mpcore per-cpu event timers, but continue to use
the GPT timer, which is fixed-frequency, as a timecounter.
Rework the cpu frequency management code for imx6.

This adds the concept of "operating points," combinations of frequency
and voltage at which the cpu is known to work correctly.  Some day these
should come from FDT data, but for now the table is hard-coded.

This also allows tuning the min and max operating frequencies.  The min
frequency is what the thermal management code will slow down to if the
core temperature gets too high.  The max frequency is what gets used if
the temperature is okay.

Normally the max cannot be set higher than the value burned into the
ocotp fuses as the chip's rated max, but there is now a new sysctl+tunable
cpu_overclock_enable; when set to non-zero it allows raising the frequency
above the ocotp value: USE WITH CARE!  (At least one of my imx6 boards
has a cpu whose ocotp values never got set correctly; they claim a max
of 792mhz, but the physical markings on the chip say it's good to 1ghz.)

Because all these values affect the entire SoC, there is a new sysctl
node, hw.imx6, where all these values live.  The values that are currently
under dev.imx6_anatop.0 should probably move to hw.imx6 too, because
"anatop" doesn't even mean anything to me, let alone to an end user.
Fix build, broken by r264025.

Sponsored by:	The FreeBSD Foundation
Implement GNU's extension of 'status' operand.  The GNU syntax is
borrowed where syntax status=noxfer means no transfer statistics
and status=none means no status information at all.

This feature is useful because the statistics information can
sometimes be annoying, and redirecting stderr to /dev/null would
mean error messages also gets silenced.

Obtained from:	OpenBSD
MFC after:	2 weeks
Correct endianness handling in getting station address from EEPROM.
While I'm here, remove aue_eeprom_getword() as its only usage is to
read station address and make it more readable.  This change is
inspired by NetBSD.
With this change, aue(4) should work on big endian architectures.

PR:	188177
Improve readability of comments for DELAY_ACK() macro.
Make -f set -a, as required by the standard.

From the original OpenBSD commit message:

  restore the traditional behavior of -f implying -a; apparently Keith
  Bostic forgot to restore it when the -f flag was put back on 2nd of
  September 1989, after being removed on 16th of August as a
  consequence of issues getting it working over NFS, so deviation from
  traditional UNIX behavior in all BSDs looks like an historical
  accident; as a side effect, this change accommodates behavior of
  this option to IEEE Std 1003.1-2008 (``POSIX.1'').

  joint work with jmc@ (who found the inaccuracy in our
  implementation), schwarze@ (who provided a detailed tracking of
  historical facts) and millert@

Submitted by: Igor Sobrado
Discussed with:  mckusick
Obtained from: OpenBSD project
MFC after:  2 weeks
- Setup both secure and non-secure timer IRQs.
  We don't know our ARM security state, so one of them will operate.
- Don't set frequency, since it's unpossible in non-secure state.
  Only rely on DTS clock-frequency value or get clock from timer.

Discussed with:	ian, cognet
Add information on standards compliance of many options.

MFC after:	2 weeks
Make C_* contants fit in 32 bits again by using 4 unused bits.

Noticed by:	bde
Some xdev fixes:

- if TARGET_ARCH is not defined and XDEV_ARCH is defined then early define
  TARGET_ARCH to the valud of XDEV_ARCH: This allow the xdev-build target
  to be able to correctly chose the compiler it needs to build
- Allow overwriting XDTP to allow a user to not chose where the xdev env will
  live in
- Fix build for gcc only xdev (like ia64) by providing the proper -B to the
  toolchain and not relying on gcc being installed already in base
- Fix TOOLS_PREFIX so the generated toolchain has the right default sysroot when
  installed intead of getting the DESTDIR one
- Fix supporting DESTDIR
- Also overwrite CXX (needed for cross building c++ libraries with clang) and
  CPP (needed to cross build some libraries when gcc is the target default
  compiler but gcc is not installed on the building host)

Discussed with:	imp
Add an extra void* cast to work around a bug in FreeBSD-gcc inherited
from Apple.
Move _b functions into the 11.x symbol version namespace.
Allow overriding xz(1) path.

Requested by:	marck
MFC After:	5 days
X-MFC-With:	r264027,r264028,r264029,r264030,r264046
Sponsored by:	The FreeBSD Foundation