These files are intended for people that want to build the agent from source and want to roll out on AIX via RPMs. You could include this somewhere around the misc directory. The spec file references the AIX init script you already ship.
I built on AIX 6.1. It might work for newer versions of Zabbix and other releases of AIX.
There is a ticket concerning the dirty patch I'm using here: https://support.zabbix.com/browse/ZBX-4204