Add support for Buffalo WZR-HP-AG300H atheros MIPS router.

Special thanks to Nicholas Esborn for the loaner router to get this
target bootstrapped.

Review:  D777
Reviewed by:    adrian
Sponsored by:   Nicholas Esborn <nick@desert.net>
Coalesce last data move and command status for read commands.

Make CTL core and block backend set success status before initiating last
data move for read commands.  Make CAM target and iSCSI frontends detect
such condition and send command status together with data.  New I/O flag
allows to skip duplicate status sending on later fe_done() call.

For Fibre Channel this change saves one of three interrupts per read command,
increasing performance from 126K to 160K IOPS.  For iSCSI this change saves
one of three PDUs per read command, increasing performance from 1M to 1.2M
IOPS.

MFC after:	1 month
Sponsored by:	iXsystems, Inc.
Shrink boot2 by a couple more bytes.

Reviewed by:    jhb
Tested by:      me, dim
Fix b64_pton output buffer overrun test for exact-sized buffer

b64_pton would sometimes erroneously fail to decode a base64 string into
a precisely sized buffer. The overflow check was a little too greedy.

Reported by:	Ted Unangst on freebsd-hackers@
Reviewed by:	loos, trasz
Obtained from:	OpenBSD
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D1218
Fix style(9).

Suggested by: jkim
Fix style(9).

Suggested by: jkim
Remove duplicated krb5

Reported by:	markj
Sort libraries definitions

Reported by:	bjk
Reinstitate send() after syslogd restarts.

In r228193 the test of CONNPRIV have been moved to before the _usleep
and send in vsyslog().  When syslogd restarts, this would prevent the
message being logged after the disconnect/connect dance for
scenario #1.

PR:		194751
Submitted by:	Peter Creath <pjcreath+freebsd gmail com>
Reviewed By:	glebius
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D1227
In preparation for using clang's -Wcast-qual:

Use __DECONST (instead of my own attempted re-invention) for the iov
parameters to jail_get/set(2).  Similarly remove the decost-ish hack
from execvp's argv, except the __DECONST is only added at very end.

While I'm at it, remove an unused variable and fix a comment typo.
Define missing libraries to be able to convert gnu, cddl and secure to LIBADD
Convert to LIBADD
Reduce overlinking
Convert svn to LIBADD reduce overlinking
Defines the libssh dependencies
Register the explicit (pthread) and implicit (for static) dependencies for
kerberos
Reduce overlinking
The framework now ensure by itself that pthread is added to the link chain
as the last component if linked to kerberos hence avoid with out any explicit
addition prevent issue like CVE-2014-8475
Convert to LIBADD
Remove all remnant ugly LD<lbname> but atf one until the aft framework knows
about LIBADD
Remove now useless USEPRIVATELIB
Convert to LIBADD