How to build pjsip for 64-bit architectures

[enisit]

Hi,

I am using this pjsip library in my react-native application and it works great. But starting from 1. August 2019, Google will require to publish 64-bit version APK together with 32-bit version. More details here: https://android-developers.googleblog.com/2019/01/get-your-apps-ready-for-64-bit.html. Is it possible to build this lib for 64-bit arch and integrate it into react-nativ-pjsip to satisfy new Google requirements?