implement some stuff to make exaple SDL app run

NOTE: the main addition in this commit is WIP support for apps which
render on an EGL surface obtained using ANativeWindow_fromSurface

currently, this EGL surface is obtained by creating a 700x700 pixel
window with GLFW (the 700x700 size is hardcoded in several places)
and only Wayland is supported

ideally, we'd want to use a wayland subsurface to position the EGL
surface above the Surface widget it's associated with (and do
whatever for X11)

src/api-impl/android/view/InputEvent.java

@@ -18,8 +18,6 @@ package android.view;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
-class InputDevice {}
-
 /**
  * Common base class for input events.
  */