Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Upgrade our copy of llvm/clang to trunk r162107. With thanks to
Benjamin Kramer and Joerg Sonnenberger for their input and fixes.

Add the 'ips' driver for the IBM (now Adaptec) ServeRAID controller
series. This driver was generously developed and released by David
Jeffreys and Adaptec. I've updated it to work with 5.x and fixed a
few bugs.

MFC After: 1 week