ROM initialisation vector now attempts to allocate a 2MB block using
PMM.  If successful, it copies the ROM image to this block, then
shrinks the ROM image to allow for more option ROMs.  If unsuccessful,
it leaves the ROM as-is.

ROM BEV now attempts to return to the BIOS, resorting to INT 18 only
if the BIOS stack has been corrupted.

_textdata_link_addr, _load_addr and _max_align in the linker scripts.
A bug in some versions of ld causes segfaults if the DEFINED() macro
is used in a linker script *and* the -Map option to ld is present.

We don't currently need to override any of these values; if we need to
do so in future then the solution will probably be to always specify
the values on the ld command line, and have the linker script not
define them at all.

compressor fixup section.

start of the non-prefix blocks in the loaded image, and rely on the
image ordering.  This should make introducing compression much easier.

image file.

causing the serial console to ignore input, because it happened to end up
linked with serial_ischar() at address 0, which core/console.c decided was
invalid).

Fix bug that caused over-allocation of .text16 and .data16 memory areas
by a factor of 16.

--nulltrap to the make target at the moment.)

install_prealloc.  I *think* these will suffice for all the 16-bit
prefixes.

advantage of the fact that we have to have a permanently-resident block
in base memory.

thinks they are.
Other bus drivers modified for consistency.

initial device, and will also allow for e.g. a device menu to be presented
to the user.