Is your feature request related to a problem? Please describe.
I'm doing development work on a linux ublk user-space filesystem driver, and I'd love to be able to use orb to do the linux build/testing since my host machine is a mac laptop.

Describe the solution you'd like
I don't need a custom ublk-drv, or really the ability to compile it (although #258 would also allow me to fix this myself). I'd just like ublk-drv to be included.

Describe alternatives you've considered
#258 might work, but I don't see any kbuild files or other things that I think I'd need to be able to actually compile a kernel module?