engine: platform: fix access to uninitialized audio subsystem when -nosound was passed

engine/platform/linux/s_alsa.c

@@ -376,6 +376,9 @@ between a deactivate and an activate.
 */
 void SNDDMA_Activate( qboolean active )
 {
+	if( !dma.initialized )
+		return;
+
 	s_alsa.paused = !active;
 
 	if( !s_alsa.paused )

engine/platform/sdl/events.c

@@ -341,7 +341,7 @@ static void SDLash_ActiveEvent( int gain )
 	{
 		host.status = HOST_FRAME;
 		IN_ActivateMouse( true );
-		if( snd_mute_losefocus.value )
+		if( dma.initialized && snd_mute_losefocus.value )
 		{
 			SNDDMA_Activate( true );
 		}
@@ -361,7 +361,7 @@ static void SDLash_ActiveEvent( int gain )
 #endif
 		host.status = HOST_NOFOCUS;
 		IN_DeactivateMouse();
-		if( snd_mute_losefocus.value )
+		if( dma.initialized && snd_mute_losefocus.value )
 		{
 			SNDDMA_Activate( false );
 		}

engine/platform/sdl/s_sdl.c

@@ -264,6 +264,9 @@ between a deactivate and an activate.
 */
 void SNDDMA_Activate( qboolean active )
 {
+	if( !dma.initialized )
+		return;
+
 	SDL_PauseAudioDevice( sdl_dev, !active );
 }
 #endif // XASH_SOUND == SOUND_SDL