myisam/ft_boolean_search.c:
  qsort_cmp -> qsort_cmp2
myisam/mi_extra.c:
  ALTER TABLE ... ENABLE/DISABLE KEYS
  mi_extra(HA_EXTRA_NO_KEYS) disables only only non-unique keys
myisam/myisamlog.c:
  qsort_cmp -> qsort_cmp2
sql/ha_myisam.cc:
  ALTER TABLE ENABLE/DISABLE KEYS
  deactivate_non_unique_index(HA_POS_ERROR) to force deactivation
sql/ha_myisam.h:
  ALTER TABLE ... DISABLE/ENABLE KEYS
sql/sql_table.cc:
  ALTER TABLE ... DISABLE/ENABLE KEYS