Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

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

Add a test program which performs some very basic tests of libmp(3).
It is by no means expected to perform a complete test of the library
for correctness, but is meant to test the API to make sure libmp (or
libcrypto) updates don't totally break the library.