include/my_global.h:
  Introduce constants to be used instead of magic numbers.
sql/field.cc:
  Polishing: use contants instead of magic numbers.
sql/ha_innodb.cc:
  Polishing: use contants instead of magic numbers.
sql/handler.cc:
  Polishing: use contants instead of magic numbers.
sql/item.cc:
  Polishing: use contants instead of magic numbers.
sql/item.h:
  Polishing: use contants instead of magic numbers.
sql/item_func.cc:
  Polishing: use contants instead of magic numbers.
sql/item_subselect.cc:
  Polishing: use contants instead of magic numbers.
sql/log_event.cc:
  Polishing: use contants instead of magic numbers.
sql/sql_base.cc:
  Polishing: use contants instead of magic numbers.
sql/sql_select.cc:
  Polishing: use contants instead of magic numbers.
sql/sql_show.cc:
  Polishing: use contants instead of magic numbers.
sql/sql_table.cc:
  Polishing: use contants instead of magic numbers.