MFC r272253:

Regenerate usb.conf

Approved by:    re, gjb
MFC r272254:
Instead of creating the full range of possible ports, try to figure
out the actual number of so-called "embedded jacks" which are present
when a USB MIDI device is attaching.

Approved by: re, gjb
MFC r272274:
Change the /var dataset in the default ZFS layout to have the
ZFS property canmount=off, making /var/db/pkg part of the / dataset, so
installed package files are consistent with the package database when
using ZFS boot environments (beadm).

PR:		193971
Reviewed by:	Shawn Webb, bcr
Approved by:	re (gjb), jmg
Relnotes:	yes
Sponsored by:	ScaleEngine Inc.
MFC r272389:

Diff reduction with kernel code: instruct the compiler that the data of
these types may be unaligned to their "normal" alignment and exercise
caution when accessing them.

PR:		194071
Approved by:	re (gjb)
MFC r270183:

  Avoid showing stale errors when nmount(2) fails.

  This should not be documented in relnotes as it still fails due to a
  race with unmounting, but no longer shows bogus details.

Approved by:	re (gjb)
MFC r271321:

  Don't cross mount boundaries when cleaning tmp files.

Approved by:	re (gjb)
Relnotes:	yes
MFC r272028:

  Make it more explicitly clear that -t will not change filename.

Approved by:	re (gjb)
MFC r271720:

  If fgets(3) fails in getbounds(), show strerror(3) if not an EOF. Also fix a
  FILE* leak in getbounds().

PR:		192032
Approved by:	re (gjb)
MFC r272288,272289:

When setting environment variables in the atrun script, use the
"export foo=bar" form instead of "foo=bar; export foo" since the
former allows the shell to catch variable names that are not valid
shell identifiers.  This will cause /bin/sh to exit with an error
(which gets mailed to the at user) and it will not run the script.

Obtained from:	OpenBSD (r1.63 millert)
Approved by:	re (gjb)
MFC r271141: Allow multiple image activators to run on the same
execution by changing imgp->interpreted to a bitmask instead of,
functionally, a bool.

Approved by:	re (gjb)