More level-polymorphism
More level-polymorphism

I'm guessing that Agda defaults levels to zero - which is fine, as long
as you don't try to use the resulting definition in a more
level-polymorphic statement (which I did).

Old-commit-hash: a2a8030a427f6f81ce80429db1805b7bd0608bf2

inc-lc/ilc-agda