GNUmifluz: TAILQ_INSERT_HEAD

do { \
 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
 (head)->tqh_first->field.tqe_prev = \
 &(elm)->field.tqe_next; \
 else \
 (head)->tqh_last = &(elm)->field.tqe_next; \
 (head)->tqh_first = (elm); \
 (elm)->field.tqe_prev = &(head)->tqh_first; \
} while (0)