-- `ilo --run-tree file.ilo`, `--run-vm`, `--run-cranelift`, and the
-- default engine all auto-run `main` on a multi-fn file when no func
-- name is supplied. Before the fix, only the default engine did:
-- * --run-tree -> arity error (`helper: expected 1 args, got 0`)
-- * --run-vm -> silent `nil`, exit 0
-- * --run-cranelift-> bare "Cranelift JIT: compilation failed"
-- All four are now consistent with the documented auto-pick-main
-- behaviour (SKILL.md: "Multi-function files require either a
-- function name argument or a function called `main`.").
helper a:n>n;+a 1
main>n;helper 41
-- run: main
-- out: 42
-- run: helper 9
-- out: 10