containing a select statement that uses an aggregating IN subquery.
Added a parameter to the function fix_prepare_information 
to restore correctly the having clause for the second execution.
Saved andor structure of the having conditions at the proper moment
before any calls of split_sum_func2 that could modify the having structure
adding new Item_ref objects. (These additions, are produced not with 
the statement mem_root, but rather with the execution mem_root.)


mysql-test/r/sp.result:
  Added a test case for bug #21493.
mysql-test/t/sp.test:
  Added a test case for bug #21493.
sql/sql_delete.cc:
  Fixed bug #21493: crash for the second execution of a function
  containing a select statement that uses an aggregating IN subquery.
  Added a parameter to the function fix_prepare_information 
  to restore correctly the having clause for the second execution.
sql/sql_insert.cc:
  Fixed bug #21493: crash for the second execution of a function
  containing a select statement that uses an aggregating IN subquery.
  Added a parameter to the function fix_prepare_information 
  to restore correctly the having clause for the second execution.
sql/sql_lex.cc:
  Fixed bug #21493: crash for the second execution of a function
  containing a select statement that uses an aggregating IN subquery.
  Added a parameter to the function fix_prepare_information 
  to restore correctly the having clause for the second execution.
sql/sql_lex.h:
  Fixed bug #21493: crash for the second execution of a function
  containing a select statement that uses an aggregating IN subquery.
  Added a parameter to the function fix_prepare_information 
  to restore correctly the having clause for the second execution.
sql/sql_update.cc:
  Fixed bug #21493: crash for the second execution of a function
  containing a select statement that uses an aggregating IN subquery.
  Added a parameter to the function fix_prepare_information 
  to restore correctly the having clause for the second execution.