llvm-toolchain-4.0 is marked for autoremoval from testing

[Debian testing autoremoval watch]

llvm-toolchain-4.0 1:4.0.1-10 is marked for autoremoval from testing on 2018-09-13

It is affected by these RC bugs:
891690: libclang-common-4.0-dev: /usr/lib/llvm-4.0/lib/clang/4.0.1/lib/ is empty on mipsel
897804: llvm-toolchain-4.0: ftbfs with GCC-8