engine: server: don't init or send voice chat in singleplayer

engine/server/sv_client.c

@@ -3458,7 +3458,7 @@ static void SV_ParseVoiceData( sv_client_t *cl, sizebuf_t *msg )
 
 	MSG_ReadBytes( msg, received, size );
 
-	if( !sv_voiceenable.value )
+	if( !sv_voiceenable.value || svs.maxclients <= 1 )
 		return;
 
 	for( i = 0, cur = svs.clients; i < svs.maxclients; i++, cur++ )

engine/server/sv_init.c

@@ -469,7 +469,8 @@ static void SV_CreateBaseline( void )
 	int		delta_type;
 	int		entnum;
 
-	SV_WriteVoiceCodec( &sv.signon );
+	if( svs.maxclients > 1 )
+		SV_WriteVoiceCodec( &sv.signon );
 
 	if( FBitSet( host.features, ENGINE_QUAKE_COMPATIBLE ))
 		playermodel = SV_ModelIndex( DEFAULT_PLAYER_PATH_QUAKE );