Fixes the SEGVs from stack overrun, but slapd tends to get hung in select.

Should eliminate individual checks for pthread_yield, sched_yield,
and pthread_detach, but they're left in for now as a redundant check.

Fix compile error when --without-threads configure option is set. Function
headers differ from prototypes in ldap_pvt_threads.h

val is 0/-1 with err in errno instead of in return val.

ldap_int_thread_pool_wrapper was called with wrong prototype  (ITS#1673)

                        ================
Written by Hallvard B. Furuseth and placed into the public domain.
This software is not subject to any license of the University of Oslo.
                        ================

ldap_int_thread_pool_wrapper() was defined with an parameter
struct ldap_int_thread_pool_s* but called with a void* argument.
Since these may have different representations, it can crash.


Hallvard B. Furuseth <h.b.furuseth@usit.uio.no>, March 2002.

	s/-L.../libraries -lldap/.../libraries/libldap/libldap.la/

whenever the Makefile is updated

Misc cleanup / lint removal

list instead of always freeing them.