audio: Fixed assertion failure if trying to use dummy backend.
diff --git a/src/audio/dummy/SDL_dummyaudio.c b/src/audio/dummy/SDL_dummyaudio.c
index 6d6d61c..acd54b8 100644
--- a/src/audio/dummy/SDL_dummyaudio.c
+++ b/src/audio/dummy/SDL_dummyaudio.c
@@ -30,6 +30,7 @@
static int
DUMMYAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
{
+ _this->hidden = (void *) 0x1; /* just something non-NULL */
return 0; /* always succeeds. */
}