- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

Change <sys/diskpc98.h> to not redefine the same symbols that are
being defined in <sys/diskmbr.h>. Instead give the symbols here a
"PC98_" prefix. This way, both <sys/diskmbr.h> and <sys/diskpc98.h>
can be included in the same C source file.

The renaming is trivial. The only gotcha is that DOSBBSECTOR is
also redefined from 0 to 1. This because DOSBBSECTOR was always
used in conjunction with an addition of 1. The PC98_BBSECTOR symbol
is defined as 1 and the expression is simplified.

Note: it is not believed that ports are seriously impacted; or at
all for that matter.

Approved by: nyan@

MFi386: r241301

add detection of serial console presence to btx and boot2-like blocks

MFi386: the part of r219452 and r236405.

- bunch of variables are turned into uint8_t.
- Remove unnecessary initializations.

Use 32-bit ufs_ino_t instead of ino_t to keep boot2 small and prevent
unnecessary 64-bit math on 32-bit machines.

Sponsored by: Google Summer of Code 2011

MFi386: revisions 232570 and 232754

Fix boot2 to handle boot config files that only contain a custom path to
a loader or kernel.

Consolidate duplicate definitions of V86_CY() and V86_ZR() which check for
the carry and zero flags being set, respectively, in <btxv86.h> and use
them throughout the x86 boot code.

Look for /boot/config in addition to /boot.config, with the former taking
precedence over the latter if it exists.

MFC after: 3 weeks

MFi386: revisions 220389 and 220392

- Mark getc() as inline, this has no effect on gcc but helps clang.
- Move getc() body before xgetc() so gcc does not emit a warning about
function having no body.

MFi386: the part of 219452

- bunch of variables are turned into uint8_t.
- the setting and reading of "fmt" in load() is removed.
- buf in printf() is made static to save space.

MFi386: revision 219186

This patch shrinks boot2 a little.

o It switches kname to be just a pointer instead of an array.
o It changes ioctl to unsigned from uint8_t.
o It changes the second keyhit limit to 3 seconds from 5.
o It removes bi_basemem/bi_extmem/bi_memsizes_valid setting.

MFi386: revision 218926

In sys/boot/i386/boot2/boot2.c, change the type of the 'opts' variable
from uint16_t back to uint32_t. The actual option bitmasks (RB_* and
RBX_*) assume at least a 32 bit variable.

Submitted by: rdivacky

MFi386: revision 218745

Remove reading of symbols from a.out loaded files.

MFi386: revision 218713

Apply a few small optimizations to boot2's code, to make it shrink a
little further.

MFi386: revision 214210

Avoid using memcpy() for copying 32bit chunks. This shrinks
the resulting code a little.

Use a cleaner expression to retrieve the memory size in pc98's boot2.c,
which also avoids NULL pointer arithmetic, as suggested by jhb. The
available space goes from 11 bytes to 7.

Reviewed by: nyan
Approved by: rpaulo (mentor)

Avoid directly manipulating a NULL pointer (which could result in
undefined behaviour) in sys/boot/pc98/boot2/boot2.c.

Reviewed by: nyan
Approved by: rpaulo (mentor)

Reimplement the boot2 for pc98 completely.
It's based on the newest i386's one and has the advantage of:

- ELF binary support.
- UFS2 filesystem support.
- Many FreeBSD slices support on a disk.

Tested by: SATOU Tomokazu ( tomo1770 _ maple _ ocn _ ne _ jp ),
WATANABE Kazuhiro ( CQG00620 _ nifty _ ne _ jp ) and
nyan

MFC after: 2 week

Happy New Year in Japan!!