How to integrate G729 codec into an existing PJSIP(2.3) library in my voip based iOS app?

I've got an old app that uses PJSIP(2.3) as I am developing a voip app. Currently, I can make voip calls through the app. I need help with adding support for g729 codec, for arm64. I would like to know the exact steps I need to perform so I'll have a well compiled pj build + g729 codec support.

How to integrate G729 codec into an existing PJSIP(2.3) library in my voip based iOS app?
 
 
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