I've given up with Android for now. I'm going to carry on without it, and maybe in the future once I've regrown my hair, I'll be able to pull it out all over again, trying to get the bloomin' thing to work.

Meanwhile..

That'll be it running as a Mac.exe (or whatever a Mac app is, nowadays)

-=-=-

My simple "Print Hello World to the console" program is compiling on Windows, Mac, iOS and seems to be working in HTML5, too.

I've spent about 6 or 7 hours installing various SDKs, NDKs and even Android Studio, but no matter what I try, I can't seem to get and Android .apk out the other side.
I've also attempted to run Linux from a thumbstick, but when it got to the point where my Laptop wouldn't even boot from the hard drive, I very rapidly undid everything I'd done in BIOS, and thankfully was presented with a working Windows desktop again!

I might, instead, try virtual-Linux, and see how that goes.
*shrugs*

Anyhoo, that's the list I'm going to start with.
Win, Mac, HTML5 and iOS.

Time to move onto Step 2.