Due to different stack contents in sdl_display_init on Ubuntu vs other distros,
an uninitialized structure is causing a crash. Zeroing the structure makes the
behavior uniform across distros, avoiding the Ubuntu crash, but doesn't fix the
underlying bugs, notably:
the return value of SDL_GetWMInfo needs to be checked, as it's currently
failing silently
the underlying reason for the failure of SDL_GetWMInfo needs to be found -
there is a GetWMINfo method in the internal SDL structure which is NULL, and
the reason for this needs to be found.
