Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Fix WARNS=2 warnings.

Use __FBSDID().
Also some minor style cleanups.

Waits for a keypress before rebooting on panic.

PR: kern/32351
Submitted by: Jonathan Mini <mini@haikugeek.com>
MFC after: 1 week

$Id$ -> $FreeBSD$

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.

Remove 'panic' command (it works), don't ask for a keypress in panic, as
exit() does. Perhaps it shouldn't?

Initial integration of the i386 bootloader and BTX.

- Discard large amounts of BIOS-related code in favour of the more compact
BTX vm86 interface.
- Build the loader module as ELF, although the resulting object is a.out,
make gensetdefs 32/64-bit sensitive and use a single copy of it.
- Throw away installboot, as it's no longer required.
- Use direct bcopy operations in the i386_copy module, as BTX
maps the first 16M of memory. Check operations against the
detected size of actual memory.

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.