The Quake sources as originally release under the GPL license on December 21, 1999

QW/client/cd_null.c

@@ -0,0 +1,31 @@
+#include "quakedef.h"
+
+void CDAudio_Play(byte track, qboolean looping)
+{
+}
+
+
+void CDAudio_Stop(void)
+{
+}
+
+
+void CDAudio_Resume(void)
+{
+}
+
+
+void CDAudio_Update(void)
+{
+}
+
+
+int CDAudio_Init(void)
+{
+	return 0;
+}
+
+
+void CDAudio_Shutdown(void)
+{
+}