map_get
ul->un_deltamap = map_get(ul, deltamaptype, DELTAMAP_NHASH);
ul->un_logmap = map_get(ul, logmaptype, LOGMAP_NHASH);
ul->un_matamap = map_get(ul, matamaptype, DELTAMAP_NHASH);
extern mt_map_t *map_get(ml_unit_t *, enum maptypes, int);