jni/main: add getting the current context
jni/main: add getting the current context

You have no idea but it seems like this is the thing which fucked
init in a lot of ways.

jeeb/mpv-android,jeeb/mpv-android,jeeb/mpv-android,mpv-android/mpv-android,jeeb/mpv-android,mpv-android/mpv-android,mpv-android/mpv-android,mpv-android/mpv-android,mpv-android/mpv-android,jeeb/mpv-android