What does MariaDB use for an IV?

I have been using MySQL 5.6 in development environment and MariaDB 5.6 in production until I needed to use encryption. MySQL 5.6 has multiple encryption modes and allows AES-256-CBC. MariaDB 5.6 only uses ECB.

So, I was working towards and upgrade to MariaDB 10, and noticed that the AES_ENCRYPT() and AES_DECRYPT() functions don’t use an IV. This is strange since CBC mode requires an IV. MySQL 5.6 and up those functions use an IV (see chart lower down in MySQL documentation). Why doesn’t MariaDB use an IV? What does MariaDB 10 use as an IV for CBC mode?

I just upgraded to MariaDB 10 and comparing the AES_ENCRYPT() function to MySQL 5.6 I noticed that it does not use an initialization vector in the function. Why? CBC mode requires an IV and so where does the IV come from for MariaDB?