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: r239063, r239064, r239069, r240852, r240854

- boot2: bunch of variables are turned into uint8_t.
- boot2: Remove unnecessary initializations.
- loader: replace ugly inb/outb re-implementations with cpufunc.h.
- Reduce diffs against i386.

MFC r235264: MFi386: improve argument passing via btxldr

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

Approved by: re (implicit)

Remove ifdef PC98.

Delete history.

Delete history.

Delete history.

MFi386: Use C (and CPP) style comments for assembler-with-cpp
sources, for lines that start with a comment.

MFi386: Get rid of unnecessary use of m4(1) by using cpp(1) instead.

Repocopied by: joe

MFi386: revision 1.13.

Sync with the following changes.

sys/boot/i386/btx/btx/Makefile 1.8
sys/boot/i386/btx/btx/btx.s 1.16 and 1.17
sys/boot/i386/btx/btxldr/btxldr.s 1.10
sys/boot/i386/loader/Makefile 1.45

Synced with following files:
src/sys/boot/i386/Makefile.inc 1.1
src/sys/boot/i386/btx/btx/btx.s 1.15
src/sys/boot/i386/btx/btxldr/Makefile 1.8
src/sys/boot/i386/btx/btxldr/btxldr.s 1.9
src/sys/boot/i386/libi386/biosdisk.c 1.29
src/sys/boot/i386/loader/Makefile 1.42
src/sys/boot/i386/loader/main.c 1.18
(entry point address of loader was not changed.)

Reviewed by: nyan

Blank out the twiddly thing when outputting the ``BTX loader'' message.

$Id$ -> $FreeBSD$

PC98 version of new boot loader. Because boot2 has not yet ported,
files in boot2 directory are copies from legacy biosboot.

Submitted by: IMAI Takeshi <take-i@ceres.dti.ne.jp>