See mkxp (https://github.com/Ancurio/mkxp), an open-source replacement for the RPGMaker engine that was used by "To The Moon" for Linux/Mac support.

As I understand it, this is not true of RPG Maker 2000/2003 (which is what EasyRPG is attempting to target). Ruby support was introduced starting in RPG Maker XP, which was released after 2003.