remove race conditions on connection close.
BROKEN: various counters for dn=monitor.
Initial testing on FreeBSD (with and without pthreads) was successfull.
Have not yet tested preemptive threading environments.
Have not built against backends other than LDBM.

	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

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.