- <sys-devel/clang-6.0.9999:=[${MULTILIB_USEDEP}] + <sys-devel/clang-7.0.9999:=[${MULTILIB_USEDEP}] compile tested, works.
Unfortunately since you forgot to bump LLVM_MAX_SLOT to 7 as well, you have ended up building Beignet against an older version of LLVM after all - and with both clang dependency and LLVM_MAX_SLOT bumped Beignet fails to compile. Feel free to reopen this bug should you come up with a patch which makes this package support llvm-7, just make sure you submit it upstream first.