myisam/mi_locking.c:
  Here we use F_EXTRA_LCK
myisam/myisamchk.c:
  lines of "locking - emulation" replaced with mi_lock_database call
myisam/myisamdef.h:
  no need for MI_TEMPORARY_TABLE
sql/ha_myisam.cc:
  We use F_WRLCK instead MI_TEMPORARY_TABLE