Building Android apps for 64-bit with ant

Hello all,
I have been searching all over the place for what command line argument/build setting/parameter/etc. I need to use to tell Ant to make a 64-bit build of an Android app I have been handed. After several days my colleague and I have been able to get it to build from the command line directly with Ant and through IntelliJ (Android Studio and Eclipse both fail). The build we get is 32-bit only and we have spent close to a week trying to find what needs to be adjusted to create a 64-bit build.

The manual makes no mention of 32 versus 64-bit compilations and Google keeps leading us to the Ant install instructions and Phone Gap/Cordova stuff.

Is there something we are missing? Does it magically start building 64-bit once we root out any libraries that are 32-bit only? Is it even possible to create a 64-bit build with Ant?

Thanks,
Mike Swan
iOS Developer

Houghton Mifflin Harcourt
Cell: 347-451-5418