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

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

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

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

Not objected to by: -current

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

Removed mature garbage (vestiges of old way of configuring bpf) and old
garbage (vestiges of old way of configuring INET).

Fixed most style bugs.

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.

udp IPv6 support, IPv6/IPv4 tunneling support in kernel,
packet divert at kernel for IPv6/IPv4 translater daemon

This includes queue related patch submitted by jburkhol@home.com.

Submitted by: queue related patch from jburkhol@home.com
Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project

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}).

Don't generate 'bpf.h' since it's not used.

$Id$ -> $FreeBSD$

Rename bpfilter to bpf.

Allow loadable interface drivers with BPF support to be loaded into a kernel
that doesn't have it. This is achieved by having minimal do-nothing stubs
enabled when there are no bpfilter devices configured.

Driver modules should be built with BPF enabled for maximum
convenience (but can be built without it for maximum performance).

Sample initial set of kld-ified modules. Not all have been completely
converted yet. These are more of a starting point. This is NOT connected
to the parent Makefile.

OK'ed by jkh (who is ever so patiently waiting)

Don't put "-I." in ${CFLAGS} here. bsd.kmod.mk now puts an absolute
path to the obj directory in ${CFLAGS}. This is actually equivalent
to "-I." since bsd.kmod.mk also puts -I- in ${CFLAGS}.

Make the LKMs compile with the INET option as a newstyle option in
opt_inet.h.

Revert $FreeBSD$ back to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

The discard, tunnel, SLIP, and PPP network interface pseudo-devices
are now dynamically loadable. It doesn't make sense to do the same
for the loopback.