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

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

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

Approved by: re (implicit)

Use __FBSDID().
Also some minor style cleanups.

Cleanup warnings. Most of these are signed/unsigned warnings, as well as
some added const's.

$Id$ -> $FreeBSD$

Fix a number of memory leaks and other memory-related disorders.

Also, unbreak the breakage introduced at the last revision of module.c.
This changes the semantics of mod_searchfile() (and mod_searchmodule())
to make the caller's responsibility freeing the buffer returned. This
is different from other functions in loader's code, and was done as a
fix for kern/9631. If someone wants to revert this to the original
behavior, don't forget to fix kern/9631 in another way.

This should also fix bin/10462, which was introduced as a result of the
first try at kern/9631 (module.c last revision).

PR: bin/10462
Submitted by: Takanori Saneto <sanewo@ba2.so-net.ne.jp>

Typo in patch application.

PR: kern/9459
Submitted by: "Daniel C. Sobral" <dcs@newsguy.com>

Enable escapes for $ to make it possible to insert variable names into
other variable values.

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.

Generic plug-and-play enumerator infrastructure. Query supplied
enumerators, crossreference returned identifiers with a text-format
database and automatically load corresponding modules and dependancies.

Allow quoted strings (single or double) for grouping whitespace separated
items. Eliminate warnings.

New commandline/script parser, supports backslash quoting and environment
variable substitution.

Submitted by: Jordan Hubbard <jkh@freebsd.org>