Add SDL_GetDefaultAudioInfo.

This API is supported on pipewire, pulseaudio, wasapi, and directsound.

Co-authored-by: Frank Praznik <frank.praznik@gmail.com>

src/audio/wasapi/SDL_wasapi.h

@@ -64,6 +64,7 @@ void WASAPI_UnrefDevice(_THIS);
 int WASAPI_PlatformInit(void);
 void WASAPI_PlatformDeinit(void);
 void WASAPI_EnumerateEndpoints(void);
+int WASAPI_GetDefaultAudioInfo(char **name, SDL_AudioSpec *spec, int iscapture);
 int WASAPI_ActivateDevice(_THIS, const SDL_bool isrecovery);
 void WASAPI_PlatformThreadInit(_THIS);
 void WASAPI_PlatformThreadDeinit(_THIS);