Fix the kernel panic in hostap mode.
rvp->beacon_mbuf was NULL in run_update_beacon().

PR:	189405
Submitted by:	Gabor Simon <gabor.simon75 at gmail.com>
MFC after:	3 days
My previous commit exposed an issue as it fixed a different
issue. lib/atf isn't a prereq_lib, since it isn't required for other
libraries to build. Remove it. The old kludge of always building it
had effectively been retired. Since we don't want to build the
libraries with the tests when we're bootstrapping, invent
MK_TESTS_SUPPORT which normally defaults to the current MK_TESTS
value, except when explicitly defined. Make lib/atf depend on it being
yes. When building the libraries set MK_TESTS to no, and
MK_TESTS_SUPPORT to the current value of MK_TESTS so that later stages
of the build work correctly. This should fix (and does for me)
people's issues with parallel builds racing between lib/atf and
libexec/atf. Since lib/atf is built during the libraries phase, the
race disappears.
Plug unnecessary PRS_NEW check in kern_procctl.

pfind does not return processes in such state.
remove/fix old code for building ipfw and dummynet in userspace
fix spelling of DEFAULT in comments...
Allow overspecification of SYSCTL type in external kernel modules.

PR:		194523
MFC after:	3 days
Actually change the USB_PORT_ROOT_RESET_DELAY definition as stated in
the r241987 commit message, instead of having users locally overriding
the value using tunables in /boot/loader.conf .

Found by:	Adam Parco
Discussed with:	Nick Hibma
Document sort_io_queue sysctls/tunables.

MFC after:	1 week
filedesc assert that table size is at least 3 in fdsetugidsafety

Requested by: kib
Untangle iSCSI authentication code by splitting off the CHAP
implementation.

Reviewed by:	mav@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Whitespace fixes.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Fix ctld(8) to not show the "auth-group <name> not assigned to any target"
warning for auth-groups assigned to a portal-group.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Remove spurious empty line.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Comment out parts about iSER; it's not implemented.

Sponsored by:	The FreeBSD Foundation
Remove misleading statement.  Bump date.

MFC after:	1 month
Sponsored by:	FreeBSD Foundation
Provide a character device allowing us to access BERI memory regions.

Sponsored by:	DARPA, AFRL
Fix ctl.conf example to use proper paths to ZVOLs.

Sponsored by:	The FreeBSD Foundation
xen: fix usage of kern_getenv in PVH code

The value returned by kern_getenv should be freed using freeenv.

Reported by:	Coverity
CID:		1248852
Sponsored by: Citrix Systems R&D
xen: allow to register event channels without handlers

This is needed by the event channel user-space device, that requires
registering event channels without unmasking them. intr_add_handler
will unconditionally unmask the event channel, so we avoid calling it
if no filter/handler is provided, and then the user will be in charge
of calling it when ready.

In order to do this, we need to change the opaque type
xen_intr_handle_t to contain the event channel port instead of the
opaque cookie returned by intr_add_handler, since now registration of
event channels without handlers are allowed. The cookie will now be
stored inside of the private xenisrc struct. Also, introduce a new
function called xen_intr_add_handler that allows adding a
filter/handler after the event channel has been registered.

Sponsored by: Citrix Systems R&D

x86/xen/xen_intr.c:
 - Leave the event channel without a handler if no filter/handler is
   provided to xen_intr_bind_isrc.
 - Don't perform an evtchn_mask_port, intr_add_handler will already do
   it.
 - Change the opaque type xen_intr_handle_t to contain a pointer to
   the event channel port number, and make the necessary changes to
   related functions.
 - Introduce a new function called xen_intr_add_handler that can be
   used to add filter/handlers to an event channel after registration.

xen/xen_intr.h:
 - Add prototype of xen_intr_add_handler.
xen: import a proper event channel user-space device

The user-space event channel device is used by applications to receive
and send event channel interrupts. This device is based on the Linux
evtchn device.

Sponsored by: Citrix Systems R&D

xen/evtchn/evtchn_dev.c:
 - Remove the old event channel device, which was already disabled in
   the build system.

dev/xen/evtchn/evtchn_dev.c:
 - Import a new event channel device based on the one present in
   Linux.
 - This device allows the following operations:
   - Bind VIRQ event channels (ioctl).
   - Bind regular event channels (ioctl).
   - Create and bind new event channels (ioctl).
   - Unbind event channels (ioctl).
   - Send notifications to event channels (ioctl).
   - Reset the device shared memory ring (ioctl).
   - Unmask event channels (write).
   - Receive event channel upcalls (read).
 - The new code is MP safe, and can be used concurrently.

conf/files:
 - Add the new device to the build system.