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 r241299: boot/console: handle consoles that fail to probe

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix a comparison that broke ``set console=vidconsole'' and even the
loader.conf line ``console="vidconsole"''.

Sponsored by: ActiveState/Sophos
MFC after: 1 week

- Add support to the loader for multiple consoles.
- Teach the i386 and pc98 loaders to honor multiple console requests from
their respective boot2 binaries so that the same console(s) are used in
both boot2 and the loader.
- Since the kernel doesn't support multiple consoles, whichever console is
listed first is treated as the "primary" console and is passed to the
kernel in the boot_howto flags.

PR: kern/66425
Submitted by: Gavin Atkinson gavin at ury dot york dot ac dot uk
MFC after: 1 week

Use __FBSDID().
Also some minor style cleanups.

$Id$ -> $FreeBSD$

- Add a new command 'lsdev' to list devices which might be likely to host
filesystems.
- New 'help' command and data in the help.* files (not yet installed),
provides topic and subtopic help, indexes, etc.
- Don't crash if the user tries to set an invalid console. Be helpful
instead.
- Expand tabs (badly) on the i386 video console.
- Some minor cosmetic changes.

Probe all consoles, not just the first. It doesn't make a lot of
difference, but might later on when we implement some sort of multi-head
console mode. Select a console after probing them all.
Don't strdup a potentially NULL return from getenv().
If we don't select an active console, choose the first regardless.
Call the console init function, at startup time and on a manual change.
The env_setenv() function needs EV_VOLATILE because it's pointing to
data that isn't malloc'ed and will cause a fault if it's freed later.

console.c
Allow the MI code to override the preferred console (eg. so that
an RB_SERIAL flag from the i386 boot2 can override the default
first active console)

isapnp.c
Use the standard format for ISA PnP IDs.

pnp.c
Allow trailing comments on lines, be less picky about line
contents.

ls.c
Cosmetic error message fix.

panic.c
Print the right arguments.

This commit was generated by cvs2svn to compensate for changes in r38465,
which included commits to RCS files with non-trunk default branches.

This is the new unified bootstrap, sometimes known previously as the
'three-stage' bootstrap.
There are a number of caveats with the code in its current state:
- The i386 bootstrap only supports booting from a floppy.
- The kernel and kld do not yet know how to deal with the extended
information and module summary passed in.
- PnP-based autodetection and demand loading of modules is not implemented.
- i386 ELF kernel loading is not ready yet.
- The i386 bootstrap is loaded via an ugly blockmap.

On the alpha, both net- and disk-booting (SRM console machines only) is
supported. No blockmaps are used by this code.

Obtained from: Parts from the NetBSD/i386 standalone bootstrap.