android: set ANDROID_NDK_HOME instead of ANDROID_NDK
Following up on !684 (closed). This fixes the openssl build on my machine.
I am not sure if ANDROID_NDK is a thing at all, but replacing it worked for me.
One note: when building Android projects with gradle, I get the warning:
Support for ANDROID_NDK_HOME is deprecated and will be removed in the future. Use android.ndkVersion in build.gradle instead.
Not sure what it implies for Cerbero, but I wanted to mention it. Happy to make more testing if that's useful.
Resolves #317 (closed)