Removing unused String declaration in Create_field::Create_field

sql/field.cc

@@ -10076,18 +10076,14 @@ Create_field::Create_field(Field *old_field,Field *orig_field)
     }
     if (!default_now)                           // Give a constant default
     {
-      char buff[MAX_FIELD_WIDTH];
-      String tmp(buff,sizeof(buff), charset);
-
       /* Get the value from default_values */
       my_ptrdiff_t diff= orig_field->table->default_values_offset();
       orig_field->move_field_offset(diff);	// Points now at default_values
       if (!orig_field->is_real_null())
       {
-        char buff[MAX_FIELD_WIDTH], *pos;
-        String tmp(buff, sizeof(buff), charset), *res;
-        res= orig_field->val_str(&tmp);
-        pos= (char*) sql_strmake(res->ptr(), res->length());
+        StringBuffer<MAX_FIELD_WIDTH> tmp(charset);
+        String *res= orig_field->val_str(&tmp);
+        char *pos= (char*) sql_strmake(res->ptr(), res->length());
         def= new Item_string(pos, res->length(), charset);
       }
       orig_field->move_field_offset(-diff);	// Back to record[0]