Instance CompSpecs : compspecs.Definition Vprog : varspecs.Definition acquire_spec := DECLARE _acquire acquire_spec.Definition release_spec := DECLARE _release release_spec.Definition makelock_spec := DECLARE _makelock (makelock_spec _).Definition spawn_spec := DECLARE _spawn spawn_spec.Definition ttask := Tstruct _task noattr.

Lemma sum_base : forall l i, fold_right Z.add i l = fold_right Z.add 0 l + i.