cmask_next_set
return cmask_next_set(m, m->base);
(cid) = cmask_next_set((m), (cid) + 1))
cmask_next_set(a, a->base) < (b->base < a_end ? b->base : a_end))
cmask_next_set(a, a->base > b_end ? a->base : b_end) < a_end)
found = cmask_next_set(m, start);
found = cmask_next_set(m, m->base);