MFC 236405:
Remove unnecessary initializations.  The BSS of boot2 is in fact
zero'd when boot2 begins execution by the _start() routine in btxcsu.S.
MFC 228161,230774,230822,236415:
Add a new -e flag to pciconf(8)'s list mode to display PCI error details.
Currently this dumps the status of any error bits in the PCI status register
and PCI-express device status register.  It also lists any errors indicated
by version 1 of PCI-express Advanced Error Reporting (AER).
MFC	r237448:

Merge changes from upstream libedit.

Here we update most of the files to at least match the
version available in NetBSD's snapshot of 20091228. This
version was chosen because it still doesn't include wide
character support (UTF-8), which involves many changes and
new files.
MFC r237458:
Import Illumos revision 13736:9f1d48e1681f
2901 ZFS receive fails for exabyte sparse files

References:
https://www.illumos.org/issues/2901

Obtained from:	illumos (issue #2901)
MFC r235153: sys/boot: add common CTASSERT definition
MFC r235154,r235158: btxldr: future-proof argument passing from
boot1/2-ish to loader
MFC r235155: i386 boot: consolidate MAXBDDEV definition
MFC r235156: i386 zfsloader: rename LIBZFS to LIBZFSBOOT
MFC r235219: cdboot, pxeldr: make use of bootargs.h instead of
redefining flag constants
MFC r235264: MFi386: improve argument passing via btxldr
MFC r235329,235343,235361,235364: zfsboot/zfsloader: support accessing
filesystems within a pool
MFC r235330: zfs boot: try to set vfs.root.mountfrom from currdev as a
fallback
MFC r235392,235394,235395: fixes and cleanups for zfs boot MFC
MFC r235390: zfs boot code: mark spa_t arguments as const where they are
used as such
fix a mismerge in r237765

sys/boot stable/8 doesn't have Makefile.spac64, instead it has
spar64-specific blocks in Makefile.
This is a direct commit.

Pointyhat to:	avg
MFC: r237219

In tty_makedev() the following construction:

dev = make_dev_cred();
dev->si_drv1 = tp;

leaves a small window where the newly created device may be opened
and si_drv1 is NULL.

As this is a vary rare situation, using a lock to close the window
seems overkill. Instead just wait for the assignment of si_drv1.
MFC 236577:
Allow the -p argument to kdump to accept either a PID or a thread ID.
MFC 237008,237271,237272,237673:
- Fix a couple of bugs that prevented windows in PCI-PCI bridges from
  growing "downward" (moving the start address down).  First, an off by
  one error caused the end address to be moved down an extra alignment
  chunk unnecessarily.  Second, when aligning the new candidate starting
  address, the wrong bits were masked off.
- Add a 'wmask' variable to hold the expression '(1ul << w->step) - 1' in
  pcib_grow_window().
- For subtractively decoding bridges, don't try to grow windows but pass
  the request up the tree in order to be on the safe side. Growing windows
  in this case would mean to switch resources to positive decoding and
  it's unclear how to correctly handle this. At least with ALi/ULi M5249
  PCI-PCI bridges, this also just doesn't work out of the box.
MFC 237334:
Move the per-thread deferred user map entries list into a private list
in vm_map_process_deferred() which is then iterated to release map entries.
This avoids having a nested vm map unlock operation called from the loop
body attempt to recuse into vm_map_process_deferred().  This can happen if
the vm_map_remove() triggers the OOM killer.
MFC 233191:
Fix madvise(MADV_WILLNEED) to properly handle individual mappings larger
than 4GB.  Specifically, the inlined version of 'ptoa' of the the 'int'
count of pages overflowed on 64-bit platforms.  While here, change
vm_object_madvise() to accept two vm_pindex_t parameters (start and end)
rather than a (start, count) tuple to match other VM APIs as suggested
by alc@.