The Ada front-end generates a "main" with a bogus
prototype as far as lli is concerned (it uses integers
rather than pointers for argv and envp).

In general, unless you are really careful about the main prototype, lli will
fail.

Perhaps the lli code should be refactored to be more forgiving?

I agree - it should at least support everything which is
ABI compatible with main, eg: a main which uses integers
instead of pointers as long as they are of pointer size.