... this isn't finished yet, in particular it lacks:
* better support for attribute sets
* support for defining functions that take attribute sets
Change-Id: Ia897fccd9d2b674b6ed12907ae297bfdcc86db48
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2237
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
Reviewed-by: tazjin <mail@tazj.in>