Add support for 16kb page size on Android

[hrydgard]

Android devices will show up with 16kb pages in the future, although there are none right now. https://developer.android.com/guide/practices/page-sizes

More information here: https://android-developers.googleblog.com/2024/08/adding-16-kb-page-size-to-android.html

[hrydgard]

This seems to not be enough. Will need to work on this - it seems TLS is broken and other things too.

Testing is most practical on a Mac with Android Studio, it turns out, as we can run ARM VMs with 16kb pages "natively" in the Android Emulator.

We probably need to switch to a newer NDK version, which will sacrifice compatibility with the very oldest devices.

Unfortunately that will require rebuilding the Android ffmpeg libraries with the new SDK and -fPIC, which is a bit painful but doable.

I'm holding off for now, but will get done before 1.19 - we need to get ahead of production devices appearing with this.