[Pkg-rust-maintainers] rustc is marked for autoremoval from testing

[Debian testing autoremoval watch]

rustc 1.10.0+dfsg1-1 is marked for autoremoval from testing on 2016-10-10

It (build-)depends on packages with these RC bugs:
835709: llvm-toolchain-3.7: FTBFS: make[1]: gcc-6.1: Command not found
835869: llvm-toolchain-3.7: FTBFS with gcc-6