Quoting Wookey <wookey@wookware.org>:
For crossing to arm-linux-gnueabi-gcc on stretch (from amd64) there is no need to build your own toolchain. Just install crossbuild-essential-armel. (and then apt-get -aarmel build-dep $package)
Works like a charm, thanks!
You only need your own where debian doesn't supply binaries
Fortunately, this is also very easy now. Things improved a lot since my last cross tool chain build - on squeeze.