Fixed line endings on WinRT source code

include/SDL_main.h

@@ -140,7 +140,7 @@ extern DECLSPEC void SDLCALL SDL_UnregisterApp(void);
  *  \ret 0 on success, -1 on failure.  On failure, use SDL_GetError to retrieve more
  *      information on the failure.
  */
-extern DECLSPEC int SDLCALL SDL_WinRTRunApp(int (*mainFunction)(int, char **), void * xamlBackgroundPanel);
+extern DECLSPEC int SDLCALL SDL_WinRTRunApp(int (*mainFunction)(int, char **), void * xamlBackgroundPanel);
 
 #endif /* __WINRT__ */