this is a bit of a hack, but since zngur cannot handle multiple trait
implementations per type yet we will have to commit to singles types.
Change-Id: I60e7b96bbeaa9fb87cf43662d4a9a5d44116bf47
they're not doing anything, and they're slightly in the way of reworking
the rust build infra. we'll add them back once that rework is completed.
Change-Id: Idde8ba3585fd08b89b4b4298349f8f58a29a9661