BUG#15842: Change in "item.cc" adding Item_sp_variable breaks compile on HP-UX 11.23
  Fix: make explicit conversion to non-constant string (char *)
  (change by anozdrin@mysql.com)


sql/item.cc:
  Make explicit conversion to non-constant string (char *)
sql/sql_trigger.cc:
  Make explicit conversion to non-constant string (char *)