MFC revisions 230804,254265,255908,256338,256345,256347-256348,256489,
257842-257845,257872,259115,259143,259276,259468-259469,259572,259686,
260260-260262,260866, and 260900 (25 revisions; summarized below)...
r230804: Fix a whitespace nit (kevlo)
r254265: (recording mergeinfo only)
r255908: Remove the is (Iceland) mirror per mail from the admins (brd)
r256338: Dump 4096 bytes from /dev/random to /entropy (des)
r256345: Rewrite the keymap module
r256347: Detect when an interface is wireless (Warren Block)
r256348: Merge dumpdev into regular services; enable (Allan Jude)
r256489: Add executable bit to docsinstall and entropy scripts
r257842: Performance and debugging enhancements
r257843: Remove ttys(5) munging from previous commit
r257844: Copy install log to deployed /var/log for debugging
r257845: Fixup to last commit
r257872: Doc fixup -- add missing .El (joel)
r259115: Prevent log file from becoming truncated
r259143: Use sed(1) /i instead of /I (eadler)
r259276: Fix `local: Not in a function' error in logfile
r259468: Ignore mouse-release command from VMware
r259469: Mask error from newaliases(1) when hostname not fully qualified
r259572: Fix `rm: /tmp/bsdinstall_etc/fstab: ..." error in logfile
r259686: Move VMware mouse-release solution
r260260: Remove what appears to be a stray debugging printf
r260261: Lower priority of open wireless access policy (gavin)
r260262: Allow bsdinstall to use WPA-Enterprise networks (gavin)
r260866: Fix bad comparison and fix file comment (Christoph Mallon)
r260900: Whitespace and style nits
MFC r263468:
  When loader(8) inspects MBR, it chooses GPT as main partition table,
  when MBR contains only PMBR entry or it is bootcamp-compatible.
  If MBR has PMBR entry and some other, the loader rejects it.

  Make these checks to be less strict. If loader decided that PMBR
  isn't suitable for GPT, it will use MBR.

  Reported by:	Paul Thornton
MFH (r237568, r255422, r255460, r255766, r255767, r255774, r255829,
  r256126, r257954, r261320, r261499, r263691, r263712): upgrade to
  OpenSSH 6.6p1 via 6.3p1, 6.4p1 and 6.5p1.

Differences relative to head:

 - No DNSSEC support since stable/9 does not have LDNS
 - Sandboxing off by default, and uses rlimit instead of Capsicum
 - ED25519 moved to the bottom of the order of preference to avoid
   "new public key" warnings
MFC r263891:

Make clang default to DWARF2 debug info format for FreeBSD 10.x and
earlier.  For head, this commit does not change anything, but it is
purely meant to be MFC'd.
MFC r263118:
Report ZVOL block size as GEOM stripesize.
Document r263970, OpenSSH update.

Sponsored by:	The FreeBSD Foundation
MFC r250143, r257079, r258086, r262670:

r250143 (benno):
  Optimize SUBDIR_OVERRIDE such that SUBDIR isn't automatically
  defined if SUBDIR_OVERRIDE is defined.

r257079:
  Fix build host pollution by avoiding calling 'uname -srp' to
  determine values for 'VERSION'.

r262670 (marcel):
  Use ${MAKE} so that we always use the same version/implementation
  of make.

r258086 (cperciva):
  Strip the -pN patch level from the VERSION string which gets
  encoded into CTF data.  Otherwise FreeBSD Update builds think every
  kernel file has changed every time there's a security advisory,
  since the FreeBSD Update build code isn't smart enough to look inside
  CTF data to ignore those changes.

Tested on:	stable/9@r263881
Sponsored by:	The FreeBSD Foundation
MFC r263775:

Avoid "cc1: warning: is shorter than expected" when using GNU cpp in
combination with dtrace scripts, which have "#!/usr/sbin/dtrace -Cs"
shebang lines.  This is because dtrace positions the file pointer after
the shebang line, before passing the file to GNU cpp.

To fix the warning, adjust the size downwards by the current position,
after a bit of sanity checking.

Suggested by:	avg
MFC r251565:

Print file names without stdio buffering to avoid mixing buffered and
unbuffered ouput.

PR:		bin/176886
MFC r263385:

Remove unused option -r from zpool.

Submitted by:	Richard Yao <ryao gentoo org>
MFC r263809

Fix crash on resume in vt(9).
Statically allocated terminal window have not initialized callout handler, so we
have to initialize it even for existing window if it is console window.

Sponsored by:	The FreeBSD Foundation
MFC r263885

o Add new vd_driver method to do bitblt with mask, named vd_maskbitbltchr.
o Move vd_bitbltchr vga's driver method to vd_maskbitbltchr.
o Implement new vd_bitbltchr method for vga driver. (It do single write for 8
	pixels, have to be a bit faster).

Sponsored by:	The FreeBSD Foundation
MFC r261521 by antoine: Add files to remove WITHOUT_NIS

PR:		misc/186412
Sponsored by:	The FreeBSD Foundation
MFC r262810, r262862, r264105, r264107:

r262810:
  Merge enabling building FreeBSD/arm images as part of the
  release build process.

r262862:
  Provide backwards-compatibility with release.conf SVNROOT
  entries that do not have a trailing '/'.

r264105:
  Add ZEDBOARD support for release builds.

r264107:
  Remove only-works-on-amd64 restriction.

* Local modifications to stable/9:
  - Set SRCBRANCH from head/ to stable/9/.

Sponsored by:	The FreeBSD Foundation
MFC r263912:
Clear the kernel grab of the FPU state on fork.
MFC	r263973;

ddb: Minor style cleanups.

#define should be followed by tab.
MFC r263966:
  Don't copy the MF flag from original IP header to ICMP error message.

PR:		188092
Sponsored by:	Yandex LLC
MFC r263969,263971:
  Don't generate an ICMPv6 error message if packet was consumed by filter.
  Remove unused label.

Sponsored by:	Yandex LLC
MFC r264027, r264028, r264029, r264030, r264046, r264073:

r264027:
  Add a new release build variable, WITH_COMPRESSED_IMAGES.

  When set to a non-empty value, the installation medium is
  compressed as part of the 'install' target in the release/
  directory.

r264028:
  Clean up trailing whitespace in release/Makefile.

r264029:
  Fix logic error.

r264030:
  If WITH_COMPRESSED_IMAGES is set, add the compressed images
  to the CLEANFILES list.

r264046:
  Use xz(1) instead of gzip(1) to compress release images
  when WITH_COMPRESSED_IMAGES is used.

r264073:
  Allow overriding xz(1) path.

Sponsored by:	The FreeBSD Foundation
MFC a modified version of r258588 (modification suggested by Mikolaj
Golub; tested stable both original and modified versions) that fixes
kernel panic when starting/stopping VIMAGE jails.

Discussed with:	rodrigc, Mikolaj Golub