GNUmifluz: SH_TAILQ_INSERT_AFTER

do { \
 if ((listelm)->field.stqe_next != -1) { \
 (elm)->field.stqe_next = (listelm)->field.stqe_next - \
 SH_PTR_TO_OFF(listelm, elm); \
 SH_TAILQ_NEXTP(listelm, field, type)->field.stqe_prev = \
 SH_TAILQ_NEXT_TO_PREV(elm, field); \
 } else { \
 (elm)->field.stqe_next = -1; \
 (head)->stqh_last = \
 SH_PTR_TO_OFF(head, &elm->field.stqe_next); \
 } \
 (listelm)->field.stqe_next = SH_PTR_TO_OFF(listelm, elm); \
 (elm)->field.stqe_prev = SH_TAILQ_NEXT_TO_PREV(listelm, field); \
} while (0)