4171 clean up spa_feature_*() interfaces
4172 implement extensible_dataset feature for use by other zpool features
Reviewed by: Max Grossman <max.grossman@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

*** 139,148 ****
--- 139,154 ----
      dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
  uint64_t zap_create_link(objset_t *os, dmu_object_type_t ot,
      uint64_t parent_obj, const char *name, dmu_tx_t *tx);
  
  /*
+  * Initialize an already-allocated object.
+  */
+ void mzap_create_impl(objset_t *os, uint64_t obj, int normflags,
+     zap_flags_t flags, dmu_tx_t *tx);
+ 
+ /*
   * Create a new zapobj with no attributes from the given (unallocated)
   * object number.
   */
  int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot,
      dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);