sql/item_cmpfunc.cc:
  Put the buff parameter back in check_stack_overrun().
sql/item_func.cc:
  Put the buff parameter back in check_stack_overrun().
sql/item_subselect.cc:
  Put the buff parameter back in check_stack_overrun().
sql/mysql_priv.h:
  Put the buff parameter back in check_stack_overrun().
sql/mysqld.cc:
  Style fixes.
sql/sp_head.cc:
  Put the buff parameter back in check_stack_overrun().
sql/sql_parse.cc:
  Put the buff parameter back in check_stack_overrun(), and added comment explaining the purpose.
sql/table.cc:
  Put the buff parameter back in check_stack_overrun().