add SDL_AndroidShowToast for https://developer.android.com/reference/android/widget/Toast
diff --git a/include/SDL_system.h b/include/SDL_system.h
index f013441..adf1c03 100644
--- a/include/SDL_system.h
+++ b/include/SDL_system.h
@@ -228,6 +228,7 @@ extern DECLSPEC SDL_bool SDLCALL SDL_AndroidRequestPermission(const char *permis
choose some value from https://developer.android.com/reference/android/view/Gravity
xOffset : set this parameter only when gravity >=0
yOffset : set this parameter only when gravity >=0
+ Returns 0 if success, -1 if any error occured.
*/
extern DECLSPEC int SDLCALL SDL_AndroidShowToast(const char* message, int duration, int gravity, int xOffset, int yOffset);