1.3.2 is the first (and so far only) version of Beignet which supports LLVM 4 and 5, both of which are now stable on amd64. Might be worth catching up, even though this is not that big of a deal given sys-devel/llvm and sys-devel/clang are now slotted by major version. It has been in the tree for quite a while now, too.
amd64 stable. Closing.