Install rust under:
usr/lib/$(DEB_HOST_MULTIARCH)/rust/$(RUST_VERSION)
override_dh_shlibdeps is based on
https://launchpad.net/~hansjorg/+archive/ubuntu/rust
usr/bin/rustc and usr/bin/rustdoc will be symlinked to the new install
location.
Signed-off-by: Jordan Justen <jljusten@gmail.com>
The configure script uses this to find the shell binary. If not set,
it will try to build i386 when on amd64 systems.
Signed-off-by: Jordan Justen <jljusten@gmail.com>