Mobile Apps with Optional GPS Capability

I noticed that many times, an app in the Android or iOS app store has GPS
features, but they are optional. But because the app "uses" GPS, user with
non-GPS-enabled tablets cannot download the app.

How do you build an app with optional GPS feature, which activates depending on
whether the user has it on their device? More specifically, how do you ensure
that users with non-GPS enabled tablets can download the app? Is that something
you'd establish at the programming level, or in registering the app with the app
store?

Thanks,