NDK/SDK Environment Variables

[rib]

Hi,

I was just looking at giving cargo-mobile a try and one initial little thing I noticed was that it didn't seem to recognise ANDROID_NDK_ROOT or ANDROID_NDK_HOME which I think are both standard environment variables for locating an Android NDK. (Normally I think I expect to switch between either of those and haven't used NDK_ROOT before)

For the SDK it also look cargo mobile considers ANDROID_HOME to be deprecated vs ANDROID_SDK_ROOT, which is incidentally the opposite of these docs: https://developer.android.com/studio/command-line/variables

I guess at this point there's not really any standard for these (lots of conflicting claims about which ones are standard) and I wonder if it could be most practical if cargo-mobile would just try all of these and maybe just show where the SDK/NDK are discovered (and by which variable) without needing to warn that any of the others are deprecated.

SDK:

ANDROID_SDK_HOME
ANDROID_SDK_ROOT
ANDROID_HOME

NDK:

ANDROID_NDK_HOME
ANDROID_NDK_ROOT
NDK_ROOT

E.g. in my case I already had my environment set up with ANDROID_NDK_ROOT and ANDROID_HOME before running cargo mobile init