Fix for bug #24912 "problems with bigint in abs() ceiling() round() truncate() mod()" and a number of related problems:

- unsigned flag was not handled correctly for a number of mathematical funcions, which led to incorrect results
- passing large values as the number of decimals to ROUND() resulted in incorrect results and even server crashes in some cases
- reverted the fix and the testcase for bug #10083 as it violates the manual
- fixed some testcases which relied on broken ROUND() behavior

sql/mysql_priv.h

@@ -1537,7 +1537,8 @@ ha_rows filesort(THD *thd, TABLE *form,struct st_sort_field *sortorder,
 		 ha_rows max_rows, ha_rows *examined_rows);
 void filesort_free_buffers(TABLE *table, bool full);
 void change_double_for_sort(double nr,byte *to);
-double my_double_round(double value, int dec, bool truncate);
+double my_double_round(double value, longlong dec, bool dec_unsigned,
+                       bool truncate);
 int get_quick_record(SQL_SELECT *select);
 int calc_weekday(long daynr,bool sunday_first_day_of_week);
 uint calc_week(TIME *l_time, uint week_behaviour, uint *year);