Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

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.

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

Add FR support to sppp (MFCronyx).

Silence on: net@, current@, hackers@.
No objections: joerg

Requested by: by many (mostly Cronyx) users for a long long time.
MFC after: 10 days

PR: kern/21771, kern/66348

sppp needs slcompress.c nowadays.

PR: 39369

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

Not objected to by: -current

Export symbols that constitute APIs defined by these
modules.

Note that in the case of 'mii' the API is not clearly
defined, and the symbols exported represent a subset
defined by current usage.

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

Make sppp a kld.