Needs work in normalizers, etc.

so #ifdef for now.

	schema engine updated (but not schema routines so things don't run yet)
	nvalues mostly populated, enough for tests 0-2 to pass
	schema routines needs lots of work
	modify/mods codes needs lots of work

  to back-bdb, back-ldbm and back-sql (the latter with limitations);
- added handling of ":dn" attributes to extended rfc2254 filters
  and to matched value filter
- altered the behavior of get_mra() when a matching rule is given:
  now it checks whether it is compatible with the attribute syntax
  and, in case it is, the given mr is used.  In case of no type,
  the check is delayed when filtering

Coverted LDAP_LOG macro to use subsystem ID int values instead of string values

Based upon patch submitted by Hallvard B. Furuseth <h.b.furuseth@usit.uio.no>.

Changed get_filter to struct bervals

   Changed AttributeDescription.{ad_cname,ad_lang} to struct berval everywhere
   Deleted ad_free() everywhere
   Added ad_mutex to init.c

The AttributeDescriptions are in a linked list hanging off of the
corresponding AttributeType.

pointer is kept for messages and to tell a filter without rule
from one with an unknown rule.  It matters.