server: warn mod developer about reaching the GoldSrc sentences limits

dlls/sound.cpp

@@ -1341,6 +1341,15 @@ void SENTENCEG_Init()
 
 	g_engfuncs.pfnFreeFile( pMemFile );
 
+	if( gcallsentences >= 2048 )
+	{
+		ALERT( at_warning, "NOTE: this mod might not work properly under GoldSource (post-anniversary update) engine: more than 2048 sentences\n" );
+	}
+	else if( gcallsentences >= 1536 )
+	{
+		ALERT( at_warning, "NOTE: this mod might not work properly under GoldSource (pre-anniversary update) engine: more than 1536 sentences\n" );
+	}
+
 	fSentencesInit = TRUE;
 
 	// init lru lists