Fix regression issue after r259248:

Some Intel XHCI controlles timeout processing so-called "TRBs" when
the final LINK TRB of a so-called "TD" has the CHAIN-BIT set.

MFC after:	1 week
Tested by:	glebius @
Start-up script for casperd daemon.

Sponsored by:	The FreeBSD Foundation
Fix periodic per-CPU timers startup on boot.

Reported by:	neel
MFC after:	2 weeks
Add a fix for Long-standing problem with VMware. Described in below links:
https://communities.vmware.com/thread/107230
https://communities.vmware.com/docs/DOC-11677

Basically, ignore the ``function 62'' and ``function 63'' interpretations
of the left/right command key when we're in the lengthiest portion of the
installation (initiated by the `auto' module).

The net effect is that you can now (once you've started the installer from
the media) escape the VM without prematurely terminating the current action
due to spurious escape sequence.

MFC after:	3 days
Mask error from newaliases(1) when the hostname is not fully qualified.

MFC after:	3 days
As per discussions on -current, re-add /var/mail (removed in r257842) but
this time with atime=on in support of various software that requires it.

Discussed on:	-current
MFC after:	3 days
Add myself to the src-committers list

Approved by:	bapt (mentor)
Accept NULL input as also meaning zero swap.

MFC after:	3 days
Enable llvm's integrated assembler for PowerPC, since it should now be
good enough for typical usage.

Requested by:	rdivacky
MFC after:	1 week
Bug-fixes and debugging improvments:
+ De-obfuscate debugging to show actual values
+ Change graid(8) syntax; s/destroy/delete/ [destroy is not invalid syntax]
+ Log commands that were previously quiet
+ Added some new comemnts and updated some existing ones
+ Add missing local for `disk' used in zfs_create_boot()
+ Use $disks instead of multiply-expanding $* in zfs_create_boot()
+ Pedantically unset variable holding geli(8) passphrase after use
+ Pedantically add double-quotes around zpool names and zfs datasets
+ Fix quotation expansion for zpool_cache entries of loader.conf(5)
+ Some limited whitespace changes

MFC after:	3 days
Migrate the sendfile_sync struct to use a UMA zone rather than M_TEMP.

This allows it to be better tracked as well as being able to leverage
UMA for more interesting/useful behaviour at a later date.

Sponsored by:	Netflix, Inc.
Improve default ZFS disk layout (tested):
+ For GPT, always provision zfs# partition after swap [for resizability]
+ For MBR, always use a boot pool to relialy place root vdevs at EOD
NB: Fixes edge-cases where MBR combination failed boot (e.g. swap-less)
+ Generalize boot pool logic so it can be used for any scheme (namely MBR)
+ Update existing comments and some whitespace fixes
+ Change some variable names to make reading/debugging the code easier
  in zfs_create_boot() (namely prepend zroot_ or bootpool_ to property)
+ Because zroot vdevs are at EOD, no longer need to calculate partsize
  (vdev consumes remaining space after allocating swap)
+ Optimize processing of disks -- no reason to loop over the disks 3-4
  separate times when we can logically use a single loop to do everything

Discussed on:	-stable
MFC after:	3 days
fletcher4 is currently the default.

Discussed on:	-current
MFC after:	3 days
De-uglify the geli(8)-setup infobox by adding a newline.

MFC after:	3 days
Add kern.geom.label.disk_ident.enable="0" to loader.conf(5).

Discussed on:	-current, -stable
MFC after:	3 days
Fix a long-standing edge-case that would result in a ghosted `zroot' pool
and subsequent headaches caused by multiple pools with the same name.
Specifically, blast away any labels on the designated swap partition.
Problem was when you install to a given layout *with* swap and then turn
around and re-install the same layout *without* swap (we weren't doing a
labelclear for the swap device, so would end up with an "UNAVAIL" status
zroot pool that may only exist in the pool cache).

MFC after:	3 days
Auto-enable 4k sector alignment when disk encryption is requested (it is
required in such a case). But don't prevent the user from pointing the
gun at his/her foot -- you can disable 4k alignment after enabling geli).

MFC after:	3 days
Add an API to deliver message signalled interrupts to vcpus. This allows
callers treat the MSI 'addr' and 'data' fields as opaque and also lets
bhyve implement multiple destination modes: physical, flat and clustered.

Submitted by:	Tycho Nightingale (tycho.nightingale@pluribusnetworks.com)
Reviewed by:	grehan@
Use the common Open Firmware PCI interrupt routing code instead of the
duplicate version in dev/fdt.

Tested by:	zbb
fix the build using __builtin_prefetch() instead of redefining prefetch()