Removed some unused variable warnings when compiling

src/modules/sound/lullaby/VorbisDecoder.h

@@ -26,6 +26,7 @@
 #include "Decoder.h"
 
 // vorbis
+#define OV_EXCLUDE_STATIC_CALLBACKS
 #include <vorbis/codec.h>
 #include <vorbis/vorbisfile.h>