I have no idea which one is "official", but I would personally prefer it if
everything switched to __ANDROID__, and I even go as far as patching the few
ANDROID places in my copy of the bionic headers to use __ANDROID__
Hum, I think we will keep both, ANDROID and __ANDROID__ in the Cmake
file for the Android build for time being. But of course it would be
nicer if we would agree on one, because the project is big and these
defines are spread.