Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r264448: Fix typo in debug/log statement.

Submitted by: Rick Miller <vmiller@hostileadmin.com>

MFC r256343,256540-256541,256544,256549,256551,256553,257939,258021,258927,
259144,259148,259470,259472,259474,259476-259478,259480-259481,259570,
259597-259598, and 261960 (24 revisions; summarized below)...
r256343: Add zfsboot module as an option for automatic configuration
r256540: Add zpool_cache_* variables to loader.conf(5)
r256541: Document BSDINSTALL_TMPBOOT in bsdinstall.8
r256544: Fix a typo when setting up loader.conf(5) GELI entries
r256549: Document zfsboot in bsdinstall.8
r256551: Bump .Dd date in bsdinstall.8
r256553: Align ZFSBOOT_BEROOT_NAME with sysutils/beadm + Solaris beadm
r257939: Validate scripted partition entry before acting on disks
r258021: Switch default MBR bootcode from /boot/boot0 to /boot/mbr
r258927: Fix early regression in enabling the Encryption feature
r259144: Fix early regression in entering passphrase for Encryption
r259148: Fix typo that broke booting from Encrypted setup
r259470: Add default /var/mail with atime=on for mail apps
r259472: Accept NULL input as also meaning zero swap
r259474: Bug fixes and debugging improvements
r259476: Improve default ZFS disk layout
r259477: fletcher4 is currently the default
r259478: De-uglify the geli(8)-setup infobox by adding a newline
r259480: Fix ghosted zroot pool issue
r259481: Auto-enable 4k alignment with Encryption
r259570: Fix "[: -eq: argument expected" error
r259597: Fix installation to 3-4+ disks
r259598: Set the cachefile property so bootpools get imported
r261960: Add zfsboot to scripted interface of bsdinstall

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 r245700,245701,245702,245706,245707,245758,245759,245760,245792,245796,
245980,246013:

Automated installation support for bsdinstall.

Add a scripting frontend. Documentation and release(7) support coming later.

Scripts take the form:

------------------------------------
PARTITIONS=ada0
DISTRIBUTIONS="kernel.txz base.txz ports.txz"

#!/bin/sh
echo "sshd_enable=YES" >> /etc/rc.conf
pkg add puppet
echo "System setup complete"
------------------------------------

The second part of the script (beginning with #!) is run in the newly
installed system after the installation onto ada0 (with default partitioning,
see scriptedpart for more complicated scenarios) is complete.