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

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 Clang in base to r108428.

This commit merges the latest LLVM sources from the vendor space. It
also updates the build glue to match the new sources. Clang's version
number is changed to match LLVM's, which means /usr/include/clang/2.0
has been renamed to /usr/include/clang/2.8.

Obtained from: projects/clangbsd

Import LLVM/clang from vendor stripped of docs/ test/ website/ www/ examples/
in llvm/ and/or llvm/contrib/clang/ respectively.

Approved by: ed (mentor)
Approved by: core

Update LLVM to 91430.