[Android] Define SDL_VIDEO_OPENGL_ES2

include/SDL_config_android.h

@@ -131,6 +131,7 @@
 
 /* Enable OpenGL ES */
 #define SDL_VIDEO_OPENGL_ES 1
+#define SDL_VIDEO_OPENGL_ES2 1
 #define SDL_VIDEO_OPENGL_EGL 1
 #define SDL_VIDEO_RENDER_OGL_ES 1
 #define SDL_VIDEO_RENDER_OGL_ES2    1