dup_mapping_rule
r[i] = dup_mapping_rule(rules[i]);
__nis_mapping_rule_t *dup_mapping_rule(
extern __nis_mapping_rule_t *dup_mapping_rule(__nis_mapping_rule_t *);
rules[dst->numRulesToLDAP] = dup_mapping_rule(src_rule);
rules[dst->numRulesFromLDAP] = dup_mapping_rule(src_rule);