manual types casting to satisfy gcc 3.2.1 compiler

sql/item_create.cc

@@ -464,8 +464,8 @@ Item *create_func_cast(Item *a, Item_cast cast_type, CHARSET_INFO *cs)
   switch (cast_type) {
   case ITEM_CAST_BINARY: 	res= new Item_func_binary(a); break;
   case ITEM_CAST_CHAR:
-    res= (cs == NULL) ? new Item_char_typecast(a) : 
-			new Item_func_conv_charset(a,cs);
+    res= (cs == NULL) ? (Item*) new Item_char_typecast(a) : 
+			(Item*) new Item_func_conv_charset(a,cs);
     break;
   case ITEM_CAST_SIGNED_INT:	res= new Item_func_signed(a); break;
   case ITEM_CAST_UNSIGNED_INT:  res= new Item_func_unsigned(a); break;