Based on discussion so far it seems that we have consensus about merging
the lang/eval and engine-related commits that precede this one as a
starting point for ongoing work in future (hopefully smaller) PRs.
This commit therefore mostly just acknowledges a small amount of unused
code in a way that it won't cause linter noise, since the future work is
likely to make these be used and so it'll be helpful to have them around as
examples to build on. (Which is, after all, the whole point of merging this
as dead code in the first place!)
This does _actually_ remove an old, now-redundant declaration of the
"compiled module instance" interface though, since that eventually ended
up in a different place and I just forgot to clean up this initial form
of it in later refactoring.
Signed-off-by: Martin Atkins <mart@degeneration.co.uk>
