CHECK constraints are not shown in I_S.TABLE_CONSTRAINTS

MySQL documentation mentions that CHECK constraints should be shown in I_S.TABLE_CONSTRAINTS when they are supported:
http://dev.mysql.com/doc/refman/5.5/en/table-constraints-table.html

I suppose it should be so in MariaDB, too.
However, MariaDB documentation does not say that (https://mariadb.com/kb/en/mariadb/information-schema-table_constraints-table/), and the constraints are not returned by the I_S table:

MariaDB [test]> create table t1 (a int, check(a>0));

Query OK, 0 rows affected (0.49 sec)

MariaDB [test]> select * from information_schema.table_constraints where table_name = 't1';

Empty set (0.00 sec)