Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

MFC r269534:

Integrate lib/libmp into the build/kyua

- Remove the .t wrapper
- Fix -Wreturn-type warnings with clang

This change has been tested on amd64/i386

Phabric: D530
Reviewed by: jmmv
Approved by: jmmv (co--mentor)
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

MFC note: src.opts.mk in the original commit was changed to
bsd.own.mk.

Integrate lib/libmp into the build/kyua

- Remove the .t wrapper
- Fix -Wreturn-type warnings with clang

This change has been tested on amd64/i386

Phabric: D530
Reviewed by: jmmv
Approved by: jmmv (co-mentor)
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

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.