Bug#836603: [Pkg-opencl-devel] Bug#836603: beignet: Please use llvm 3.8 or, better, 3.9

[Rebecca N. Palmer]

Control: severity -1 minor

This package depends on llvm-toolchain-3.7.
Only on kfreebsd-* (which aren't release architectures, and can't build 
anything more recent).

(If you used a checking tool, see #836342.)