The original Quake 2 sources as originally released under the GPL license on December 21, 2001.

null/cd_null.c

@@ -0,0 +1,31 @@
+#include "../client/client.h"
+
+void CDAudio_Play(int 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)
+{
+}