Fix NOMIXER

src/sdl/sdl_sound.c

@@ -1409,6 +1409,9 @@ UINT32 I_GetSongPosition(void)
 	return 0;
 }
 
+void I_UpdateSongLagThreshold (void) {}
+void I_UpdateSongLagConditions (void) {}
+
 /// ------------------------
 //  MUSIC PLAYBACK
 /// ------------------------