tree data BUGFIX missing macro

Author: michalvasko

src/tree_data.h

@@ -1139,7 +1139,7 @@ LIBYANG_API_DECL LY_ERR lyd_any_copy_value(struct lyd_node *trg, const union lyd
  * @param[in] node Data node to use.
  * @return Schema node represented by data @p node, NULL if there is none.
  */
-const struct lysc_node *lyd_node_schema(const struct lyd_node *node);
+LIBYANG_API_DECL const struct lysc_node *lyd_node_schema(const struct lyd_node *node);
 
 /**
  * @brief Create a new inner node in the data tree.