use ldap_pvt_ routines (replacing old lthread impl)

	shutdown without busy loop, explicit yield func no longer mandatory
	use pthread_detach() to detach threads (instead of creating them
		in a detached state)
	pthread_create error reporting
	moved declarations to init.c
Import configure changes:
	revamp res_search check
	remove strtok_r check

to add a simple mutex.  Should be two (proto-slap.h & init.c).

thread shutdown codes.

  Plug some memory leaks
  Change overlapping `strcpy( x, y )' to `SAFEMEMCPY( x, y, strlen( y ) + 1 )'

Includes everything but ldapext & ldap.conf changes.

    Changed LDBM default to sync on writes
    Added mail500 BOUNCEFROM patch
    Added dbcachenowsync option
    Fixed slapd/ldbm id2children bug
    Fixed slapd/shell newline bug
    Fixed whois++ get_dn leak
    Fixed DEC OSF1 (alpha) support
    Fixed r/w lock initialization on non-final Pthreads
    Fixed slapd/slurpd file unlock bugs
    Fixed slurpd string translation bug
    Fixed slurpd/st mutex unlock bug
    Moved detach() to -llutil
    Added lutil_passwd() to -llutil
    Autoconf:
        Fixed thread detection
        Removed gcc -traditional tests
        Changed --enable-dns to require --enable-referrals
        Added -lresolv tests for ldapd and LDAP_DNS
        Added basic ISODE checks
        Added pwd.h &  getpwuid() tests
        Added sys/resource.h test
    Updated NT support (now builds ud)
    Removed lint