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

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

And isa_if.h

Add pccbb_isa.c and pccbb_pci.c

Fix this pending the decision of which of the redundant
sys/modules/{pc,}cbb/Makefile to remove.

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

Not objected to by: -current

Turn on unconditional symbol export for modules whose API is
not clear enough, will require additional analysis, or will
require some input from their maintainers.

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.

Removed special rules for building and cleaning device interface files
and empty options files. The rules are now generated automatically in
bsd.kmod.mk. Cleaned up related things ($S and ${CLEANFILES}).

Add modules for cardbus and the cardbus bridge driver. Files needed
to build these to be committed next.

Again, not added to sys/modules/Makefile