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

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

Move adding -DPC98 to CFLAGS from each modules to sys/modules/Makefile.inc.

Drop <bsd.man.mk> support from <bsd.kmod.mk>.

Not objected to by: -current

Build modules from the main src/sys tree.
Tidy up some loose ends.. there were extra -I's being added to CFLAGS for
no reason.

Added PC-98 apm support.

Submitted by: MURAMATSU Atsushi <amura@ma3.seikyou.ne.jp>

Use a consistent style and one much closer to the rest of /usr/src

Use .include <bsd.kmod.mk> to get to ../../*/conf/kmod.mk instead of
encoding the relative path.

Pull in sys/conf/kmod.mk, rather than /usr/share/mk/bsd.kmod.mk.
This means that the kernel can be totally self contained now and is not
dependent on the last buildworld to update /usr/share/mk. This might
also make it easier to build 5.x kernels on 4.0 boxes etc, assuming
gensetdefs and config(8) are updated.

Add the apm_saver syscons screen saver module.

apm_saver uses the apm_display() routine from the apm system to
"suspend" the "display" part of the machine.

This is beneficial for some laptops (or other machines with
non-traditional displays) that choke on the 'green' saver's
effect.

Another way of looking at this is that it's the same as a screen
saver that does an 'apm -d 0' to blank the display and an 'apm -d 1'
to bring it back. One probably ought to use these commands to make
sure the effect will be correct before using it unattended.