* Win32 compilation fixes (mingw includes dirent)

* Win32 compilation fixes (mingw includes dirent)
* configure now checks for ddraw.h and not directx.h
* vout_directx doesn't include directx.h anymore (this file isn't part of
    the directx sdk)
* moved all the stuff from aout_waveout.c directly into waveout.c (I don't
    know what I was thinking about when I created these two files ;-)
* until we fix the audio buffer underrun problem, waveout will be the
    default audio output on win32 (instead of directx).