bool is_achievement_needed(struct achievement *pach, requirers_cb cb, void *data)
bool is_multiplier_needed(struct multiplier *pmul, requirers_cb cb, void *data)
bool is_counter_needed(struct counter *pcount, requirers_cb cb, void *data)
bool is_tech_needed(struct advance *padv, requirers_cb cb, void *data)
bool is_terrain_needed(struct terrain *pterr, requirers_cb cb, void *data)
bool is_good_needed(struct goods_type *pgood, requirers_cb cb, void *data)
bool is_government_needed(struct government *pgov, requirers_cb cb, void *data)
bool is_utype_needed(struct unit_type *ptype, requirers_cb cb, void *data)
void(* requirers_cb)(const char *msg, void *data)
bool is_extra_needed(struct extra_type *pextra, requirers_cb cb, void *data)
bool is_building_needed(struct impr_type *pimpr, requirers_cb cb, void *data)