Style cleanups.

Submitted by:	Mariusz Zaborski <oshogbo@FreeBSD.org>
Sponsored by:	Google Summer of Code 2013
Reviewed by:	pjd
MFC after:	1 month
Increase the microcode max size to 16K to accomodate more recent Intel
firmware.
Sandbox rwho(1) using capability mode and Capsicum capabilities.
rwho(1) gets only read-only access to /var/rwho/ directory.

Submitted by:	Mariusz Zaborski <oshogbo@FreeBSD.org>
Sponsored by:	Google Summer of Code 2013
Reviewed by:	pjd
MFC after:	1 month
Few more style nits.

MFC after:	1 month
Style cleanups.

Submitted by:	Mariusz Zaborski <oshogbo@FreeBSD.org>
Sponsored by:	Google Summer of Code 2013
Reviewed by:	pjd
MFC after:	1 month
The whole sending functionality was implemented within signal handler,
which is very bad idea. Split sending and receiving in two processes,
which fixes this problem and will help to sandbox rwhod.

Submitted by:	Mariusz Zaborski <oshogbo@FreeBSD.org>
Sponsored by:	Google Summer of Code 2013
Reviewed by:	pjd
MFC after:	1 month
Sandbox rwhod(8) receiver process using capability mode and Capsicum
capabilities.

rwhod(8) receiver can now only receive packages, write to /var/rwho/ directory
and log to syslog.

Submitted by:	Mariusz Zaborski <oshogbo@FreeBSD.org>
Sponsored by:	Google Summer of Code 2013
Reviewed by:	pjd
MFC after:	1 month
1) POSIX requires rand(3) return values to be in the [0, RAND_MAX] range,
but ACM formula we use have internal state (and return value) in the
[1, 0x7ffffffe] range, so our RAND_MAX (0x7fffffff) is never reached
because it is off by one, zero is not reached too.

Correct both RAND_MAX and rand(3) return value, shifting last one
to the 0 by 1 subtracted, resulting POSIXed [0, 0x7ffffffd(=new RAND_MAX)]
range.

2) Add a checks for not overflowing on too big seeds. It may happens on
the machines, where sizeof(unsigned int) > 32 bits.

Reviewed by:    bde [1]
MFC after:      2 weeks