Limit the new order of the pending sound lists to baseq2 and the addons.

The new ordering was introduced in 16ee007, fixing some problems with
the wrong sound getting played when an entity triggers several sound at
the same timestamp. This broke the behavior of the mods, in #558 dday
was mentioned, muzzle flashe sound prevent the firing sound from getting
played.

Since we don't control the source of all mods, add a simple band aid
fix: Use the new ordering for baseq2, xatrix and rouge. Use the old
ordering for everything else.

An alternative approach is being discussed in #564.

src/client/sound/sound.c

@@ -722,11 +722,25 @@ S_StartSound(vec3_t origin, int entnum, int entchannel, sfx_t *sfx,
 		}
 	}
 
-	/* sort into the pending sound list */
-	for (sort = s_pendingplays.next;
-		 sort != &s_pendingplays && sort->begin <= ps->begin;
-		 sort = sort->next)
+	cvar_t *game = Cvar_Get("game",  "", CVAR_LATCH | CVAR_SERVERINFO);
+
+	if ((strcmp(game->string, "") == 0) ||
+			(strcmp(game->string, "rogue") == 0) ||
+			(strcmp(game->string, "xatrix") == 0))
 	{
+		for (sort = s_pendingplays.next;
+				sort != &s_pendingplays && sort->begin <= ps->begin;
+				sort = sort->next)
+		{
+		}
+	}
+	else
+	{
+		for (sort = s_pendingplays.next;
+				sort != &s_pendingplays && sort->begin < ps->begin;
+				sort = sort->next)
+		{
+		}
 	}
 
 	ps->next = sort;