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

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

Clean some 'svn:executable' properties in the tree.

Submitted by: Christoph Mallon
MFC after: 3 days

Per email to arch@ a little while ago (that was greeted with silence),
prefer the more common > ${.TARGET} over > opt_foo.h in modules
makefiles.

Fix our ioctl(2) implementation when the argument is "int". New
ioctls passing integer arguments should use the _IOWINT() macro.
This fixes a lot of ioctl's not working on sparc64, most notable
being keyboard/syscons ioctls.

Full ABI compatibility is provided, with the bonus of fixing the
handling of old ioctls on sparc64.

Reviewed by: bde (with contributions)
Tested by: emax, marius
MFC after: 1 week

Let modules use the kernel's opt_*.h files if built along with
the kernel by wrapping all targets for fake opt_*.h files in
.if defined(KERNBUILDDIR). Thus, such fake files won't be
created at all if modules are built with the kernel.

Some modules undergo cleanup like removing unused or unneeded
options or .h files, without which they wouldn't build this way
or the other.

Reviewed by: ru
Tested by: no binary changes in modules built alone
Tested on: i386 sparc64 amd64

Fix my recent breakage of some modules.

digiio.h has moved to /usr/include/sys

Add a ``digi'' driver.

This driver supports PCI Xr-based and ISA Xem Digiboard cards.
dgm will go away soon if there are no problems reported. For now,
configuring dgm into your kernel warns that you should be using
digi. This driver is probably close to supporting Xi, Xe and Xeve
cards, but I wouldn't expect them to work properly (hardware
donations welcome).

The digi_* pseudo-drivers are not drivers themselves but contain
the BIOS and FEP/OS binaries for various digiboard cards and are
auto-loaded and auto-unloaded by the digi driver at initialisation
time. They *may* be configured into the kernel, but waste a lot
of space if they are. They're intended to be left as modules.

The digictl program is (mainly) used to re-initialise cards that
have external port modules attached such as the PC/Xem.