Added connection initialisation and destruction notification. Now backends can register functions in backend_info.bi_connection_init and backend_info.bi_connection_destroy that will be called when a connection is initialized or destroyed.

LDAP_OPT_MATCH_STRING to ldap.h and libldap/options.c.

Move cache_return_entry_w() out of ldbm_back_add when the add is successful.
This change breaks back-bdb2, it needs equvalent changes of those in back-ldbm.

Provision for a bdb2 backend-specific DB file suffix.
Fix of the double-open of backend types.

the backend type info structure.  Use this filed to control open
and close such that backend's without databases are skipped.

Integration into ./configure ( --enable-bdb2 ).
Adaptation of the test-suite ( 'make' -> ldbm; 'make bdb2-local' -> bdb2 ).
Minor fixes in slapd/libldbm.

Separates per backend type from per backend database initialization
	and startup.  Also supports per type / per backend shutdown.
New frontend startup/shutdown routines are also provided:
	slap_init() slap_startup() slap_shutdown() slap_destroy()
New frontend->backend startup/shutdown is managed by:
	backend_init() backend_startup() backend_shutdown backend_destroy
backend_init() now calls bi_init() to initial all function pointers
for the backend (excepting bi_init() which is now the only hardcoded
entry point).  New entry points are detailed in slap.h struct
backend_info.  backend_info is a per database type structure.
Besides the new startup/shutdown entry points, the new interface
also supports per backend type configuration options.  One could have:

	backend bdb2	(new Berkeley DB 2 backend)
	bdb2_home	/directory

	database bdb2
	...

	*** This code is fairly experimental ***
	*** Much cleanup and testing is still needed ***

see slap.h for details on struct backend_db and backend_info.

frontend->backend interface.

initialization after reading slapd.conf, and before starting the daemon

	Likely broke things for non-posix threadings....

Update -lldap_r implementation to:
	remove attribute support
	hide thread detachment
	provide concurrency accessors
	provide initialization function
	fix gethostby{addr,name}_r codes (not coverred by HAVE_REENTRANT_FUNCTIONS)
Update servers/libraries to use ldap_pvt_thread_ calls.
Cleanup server codes (no #ifdef HAVE_PTHREAD_THIS or _THATs)!
Removed -llthread

Update slap_op to maintain dn and ndn (derived from conn->c_dn).
Update ldbm_back_bind to return actual bound dn (including rootdn)
	for use in slapd_conn.  Other backends use client dn.
Modify other codes to use ndn (normalized uppercase dn) most everywhere.
Aliasing, Suffixing and modrdn could use more work.
Applied suffixing to compare and modrdn.

John's still working on the 'perl-test' (the perl backend test module).

Resolved deadlock by passing target entry to be_group and using
this if dn same as bdn.  It might actually be safer to check
entry ids instead of dns.
Resolved bogus add to cache after failed acl check by deferring
cache add until after parent/acl checks have successful been
completed.
Eliminated race condition caused by concurrent adds
of same dn by adding 'li_add_mutex' around the critical section
of code (most of ldbm_back_add).
This code is preliminary and still needs significant testing.

mutex declaration should be moved from slapd/main.c to slapd/init.c
so we don't have ripple changes through slapd/tools.

to after other suffix checks.

Updated other codes as needed.

Remove MD5 and SHA1 options (both are now always on).  Rename
functions to be lutil_ instead of ldap_.
Create --enable-cleartext option.  Default is currently 'on'.

Most function and variable definitions are now preceded by its extern
definition, for error checking.  Retyped a number of functions, usually
to return void.  Fixed a number of printf format errors.

API changes (in ldap/include):
  Added avl_dup_ok, avl_prefixapply, removed ber_fatten (probably typo
  for ber_flatten), retyped ldap_sort_strcasecmp, grew lutil.h.

A number of `extern' declarations are left (some added by protoize), to
be cleaned away later.  Mostly strdup(), strcasecmp(), mktemp(), optind,
optarg, errno.

2. update print_acl() a bit and call it during aclparse if LDAP_DEBUG_ACL

Not quite sure if the entry lock handling is correct yet.

Must enable -DLDAP_ALLOW_NULL_SEARCH_BASE to use.

	adds POSIX RegEx (and removes BSD re_comp/re_exec) support.
* POSIX RegEx is not currently included in the distribution, however
	we will probably add Henry Spencer's REGEX library soon.
* ACL Group functionality is also included in this merge!