Никак, она там включена по умолчанию.
Просто устанавливаете MariaDB 10, и всё подхватится.
By default, MariaDB uses the XtraDB storage engine, a performance enhanced fork of the InnoDB storage engine. For compatibility reasons, the system variables still retain their original innodb prefixes, and where the text in this knowledgebase refers to InnoDB, it can usually be understood as referring to the XtraDB fork.
Note that it is possible to use InnoDB as a plugin in MariaDB instead of XtraDB. See Using InnoDB instead of XtraDB.
https://mariadb.com/kb/en/mariadb/xtradb-and-innodb/ 
