Remove $FreeBSD$: two-line nroff pattern

Remove /^\.\\"\n\.\\"\s*\$FreeBSD\$$\n/

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

Rename all symbols in libmp(3) to mp_*, just like Solaris.

The function pow() in libmp(3) clashes with pow(3) in libm. We could
rename this single function, but we can just take the same approach as
the Solaris folks did, which is to prefix all function names with mp_.

libmp(3) isn't really popular nowadays. I suspect not a single
application in ports depends on it. There's still a chance, so I've
increased the SHLIB_MAJOR and __FreeBSD_version.

Reviewed by: deischen, rdivacky

- Import the HEAD csup code which is the basis for the cvsmode work.

Add a reference to bn(3) for those looking for functional multiprecision
integer arithmetic.

Fixed spelling of rpow in rpow's prototype.

Don't claim to be mp(3).

Fix markup and a couple of thinkos.

Submitted by: ru

Add a manual page for the libmp interface. Some of the descriptions
great, but then again neither is the interface it's documenting.