Replace home-grown CTL IO allocator with UMA.

Old allocator created significant lock congestion protecting its lists
of preallocated I/Os, while UMA provides much better SMP scalability.
The downside of UMA is lack of reliable preallocation, that could guarantee
successful allocation in non-sleepable environments.  But careful code
review shown, that only CAM target frontend really has that requirement.
Fix that making that frontend preallocate and statically bind CTL I/O for
every ATIO/INOT it preallocates any way.  That allows to avoid allocations
in hot I/O path.  Other frontends either may sleep in allocation context
or can properly handle allocation errors.

On 40-core server with 6 ZVOL-backed LUNs and 7 iSCSI client connections
this change increases peak performance from ~700K to >1M IOPS!  Yay! :)

MFC after:	1 month
Sponsored by:	iXsystems, Inc.
Add ip_gre.h to ObsoleteFiles.inc.

Sponsored by:	Yandex LLC
Make it possible to specify flags for autofs daemons in rc.conf.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Add a sysctl `net.link.tap.deladdrs_on_close' to configure whether tap
should delete configured addresses and routes when the interface is
closed.  Default is enabled (preserve current behaviour).

MFC after:	1 week
Add busdma sync ops before reading and after modifying the descriptor rings.

This was previously working by accident because BUSDMA_COHERENT_MEMORY has
always been set to strongly-ordered on arm.  Now we're moving towards
normal-uncacheable (what might be called write-combining on other platforms)
and using the proper sync ops will be more important.  Of course, that
opens the question of just what is the "proper" sync op for shared
concurrent dma access as opposed to accesses where the handoff of control
of the memory has well-defined sequence points that match the available
busdma sync operations.
Properly initialize the capability rights for vnodes exported to procstat
that aren't for file descriptors (cwd, jdir, tracevp, etc.).

Submitted by:	Mikhail <mp@lenta.ru>
Add a bus_get_domain() wrapper around BUS_GET_DOMAIN().  Use this to add
a new per-device '%domain' sysctl node that returns the NUMA domain a
device is associated with if it is associated with one.

Note that this API is still a WIP and might change before 11.0 actually
ships.

Differential Revision:	https://reviews.freebsd.org/D930
Reviewed by:	kib, adrian
For now, disable using -fsanitize=bounds for the libc ssp tests, when
using clang 3.5.0, until the runtime support (via compiler-rt) is added.
Otherwise, this would lead to link errors about missing support
libraries.
Implement LIBADD

LIBADD will automatically set DPADD and LDADD when needed including their
dependencies, LIBADD automatically handles private and internal libs so that
the end user Makefile does not have to care about it.

This allows to reduce overlinking on the base system leaving the framework get
the dependencies properly.

It also allows to built components binaries statically.

To use it:

Replace:
DPADD=	${LIBARCHIVE} ${LIBSSL}
LDADD=	-larchive -lssl

by:
LIBADD=	archive ssl

Differential Revision:	https://reviews.freebsd.org/D1209
Reviewed by:	brooks imp
Correctly specify -L for internal and private libs
Convert to LIBADD.

Reviewed by:	bapt
Import libgpio.

This is a thin wrapper around the kernel interface which should make
it easier to write GPIO applications.  gpioctl(8) will be converted to
use this library in a separate commit.

Differential Revision:	https://reviews.freebsd.org/D1183
Reviewed by:	adrian, loos
Discussed on:	arm@, embedded@
Relnotes:	yes
Skip L2 addresses lookups for p2p interfaces.

Discussed with:	melifaro
Sponsored by:	Yandex LLC
Convert mandoc to LIBADD

While here remove the ugly LDMANDOC
Convert makefs to LIBADD

Add definition of libnetbsd in src.libnames.mk
Each time something links to sqlite3 it should link to pthread
Avoid code duplication by directly adding _INSTALLLIBS and _PRIVATELIBS into
_LIBRARIES

Reported by:	emaste
Fix dependencies in case of building statically
Fix typo
Forgot to convert demandoc along with mandoc