Change prefixes to make eyeballing .dbb files easier

Added initial DN_INDICES code behind #ifdef DN_INDICES.
  Generates only equality index.  Will add parent and subtree indices next.

NULL does not meet basic syntax rules.

  added slap_ and ldbm_ to many structures
  added typedefs to many structures
  used typedefs
New main.c argument parsing with ldap url support (replacing -a address).
New sockaddr_in handling and support for multiple listeners.

Includes support for update referral for each replicated backend.
	Reworked replication test to use update referral.
Includes major rewrite of response encoding codes (result.c).
Includes reworked alias support and eliminates old suffix alias codes
(can be emulated using named alias).
Includes (untested) support for the Manage DSA IT control.
Works in LDAPv2 world.  Still testing in LDAPv3 world.
Added default referral (test009) test.

I rather have NOID printed as "-1".  It it could argued that ID
should be signed.

cache_set_state() and state args are no history.
Move cache_entry_cmp() and friends to slapd/entry.c to allow sharing
of functions between backends..  Renamed to entry_cmp().

The new e_private field can be used for any backend purpose.  In LDBM,
it's used to point th the private entry info struct.  The LDBM entry
info struct is only visible to the LDBM cache.
WARNING: This change has not be ported to other backends!  Breakage is likely.

Assume entry was deleted from underneath the dn2entry call,  hence
processing is same as if NOID had been returned.

Introduction of ldbm_datum_init().
Patch for non-NULL pointer test befor call to ldbm_datum_free().

if strdup fails.  This is better than not checking, but we should
add orderly shutdown.

Modified users of this code to free matched if set.

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.

Change backend struct option to li_dbcachewsync.

	Derived from public posting to ldap@umich.edu
	by Kurt Spanier <kurt.spanier@zdv.uni-tuebingen.de>
	See Make-common.dist for DB2 options