Here are a couple of patches to update the rust package to work without networking and bump it to version 1.16.0
A couple of notes
The new rustbuild build system is disabled for the 1.16.0 bump. It uses rust and cargo for the build system instead of Makefiles. This means it will once again need networking, without polluting the sources list with all the dependent crates. Builds with rustbuild enabled are not working anyway, so this isn't such a big issue at the moment. However, the Makefiles are being removed and rustbuild will be the only option once 1.17.0 hits stable.
- Bootstrapping the compiler from the existing rust and cargo packages does not work (rustc fails to compile with can't find crate for 'core' or can't fine crate for 'std'). I have not had a chance to look into if we are able to work around this to bootstrap using existing packages.