include/myisam.h:
  Don't assume too big tempoary disks
myisam/mi_check.c:
  Don't assume too big tempoary disks
myisam/mi_static.c:
  Don't assume too big tempoary disks
myisam/myisamdef.h:
  Fix type
sql/ha_myisam.cc:
  Set myisamchk to use MySQL temporary disk space
sql/slave.cc:
  Fix parameters
sql/sql_lex.h:
  Added backup_dir