[DF] Avoid forward declarations of Define'd types
[DF] Avoid forward declarations of Define'd types

Either the interpreter knows them, or we alias them to `void`.
Just as before, the end result is that if users return a type
that is unknown to the interpreter from a Define, and then try
to read that Define'd column from jitted RDF nodes, the interpreter
(and consequently RDF) errors out.

karies/root,karies/root,olifre/root,karies/root,karies/root,olifre/root,karies/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,olifre/root,olifre/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root,karies/root