As you already know, there is an ongoing series of patches to enable Rust
support in the kernel. The latest version of this series can be found here:
https://lists.openembedded.org/g/openembedded-core/topic/patch_v7_00_14_enable_rust/118136908

With the newest version, the relevant changes are now controlled via the 
KERNEL_RUST_SUPPORT variable. Therefore, instead of introducing additional
dependencies directly, Can you make it optional by using the same variable.

Regards,
Deepesh