Use the included Khronos headers on Android so we can create Core OpenGL contexts when building with older SDK

include/SDL_egl.h

@@ -24,7 +24,7 @@
  *
  *  This is a simple file to encapsulate the EGL API headers.
  */
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) && !defined(__ANDROID__)
 
 #include <EGL/egl.h>
 #include <EGL/eglext.h>

src/core/android/SDL_android.c

@@ -29,7 +29,6 @@
 
 #include "SDL_system.h"
 #include "SDL_android.h"
-#include <EGL/egl.h>
 
 #include "keyinfotable.h"