-void spa_history_internal_log(history_internal_events_t event, spa_t *spa,
- dmu_tx_t *tx, cred_t *cr, const char *fmt, ...);
+extern void spa_history_internal_log(history_internal_events_t event,
+ spa_t *spa, dmu_tx_t *tx, cred_t *cr, const char *fmt, ...);
+extern void spa_history_log_version(spa_t *spa, history_internal_events_t evt);