c8rtombstate
struct c8rtombstate *S;
S = (struct c8rtombstate *)(void *)ps;
__CTASSERT(offsetof(struct c8rtombstate, mbs) <= sizeof(mbstate_t));
offsetof(struct c8rtombstate, mbs));
__CTASSERT(alignof(struct c8rtombstate) <= alignof(mbstate_t));