Added missing source file.

sdl.mod/source.bmx

@@ -79,6 +79,7 @@ Import "SDL/src/video/android/SDL_androidevents.c"
 Import "SDL/src/video/android/SDL_androidgl.c"
 Import "SDL/src/video/android/SDL_androidkeyboard.c"
 Import "SDL/src/video/android/SDL_androidmessagebox.c"
+Import "SDL/src/video/android/SDL_androidmouse.c"
 Import "SDL/src/video/android/SDL_androidtouch.c"
 Import "SDL/src/video/android/SDL_androidvideo.c"
 Import "SDL/src/video/android/SDL_androidwindow.c"