Emscripten: Fixed not including SDL_internal.h.

src/joystick/emscripten/SDL_sysjoystick_c.h

@@ -19,7 +19,7 @@
  3. This notice may not be removed or altered from any source distribution.
  */
 
-#include "SDL_config.h"
+#include "../../SDL_internal.h"
 
 #ifdef SDL_JOYSTICK_EMSCRIPTEN
 #include "../SDL_sysjoystick.h"