full support for HA_READ_PREFIX_LAST_OR_PREV in MyISAM
protected by #if NOT_IMPLEMENTED_YET in opt_range.cc as not all table handlers support it


BitKeeper/etc/ignore:
  Added configure.lineno innobase/configure.lineno innobase/stamp-h1 myisam/rt_test.MYD myisam/rt_test.MYI stamp-h1 to the ignore list
include/my_base.h:
  support for HA_READ_PREFIX_LAST_OR_PREV
myisam/mi_search.c:
  full support of HA_READ_PREFIX_LAST_OR_PREV in MyISAM
myisam/mi_static.c:
  full support of HA_READ_PREFIX_LAST_OR_PREV in MyISAM
sql/opt_range.cc:
  support for HA_READ_PREFIX_LAST_OR_PREV
  protected by #if NOT_IMPLEMENTED_YET, not all table handlers support it
sql/sql_handler.cc:
  support for HA_READ_PREFIX_LAST_OR_PREV