Modified clients to reduce use of ldapconfig.h.edit.
ldap_{get,set}_option support is relatively complete.  Needs
to be extended to support other "features" of OpenLDAP.

Fix old -pthread -lmach ... support to check for -lc_r instead of -lc.

  ifndef HAVE_PTHREAD_KILL pthread_kill() code and prototype.
  Fix HAVE_FUNC_PTHREAD defines from previous change.

Fix pthread_attr_init/destroy pthread draft4 compatibility.

  configure generates ldap_features.h based from ldap_features.h.in
  LDAP_REFERRALS -> LDAP_API_FEATURE_OPENLDAP_V2_REFERRALS
  LDAP_DNS -> LDAP_API_FEATURE_OPENLDAP_V2_DNS

Add openldap_ldap_initialize() call to ldap_init/ldap_open/ldap_get/set_options.

Updated portable.h.nt based upon portable.h.in (1.11).

initialize_client() should return void.  Fix and forward declaration.

Change backend struct option to li_dbcachewsync.

Remove AC_GCC_TRADITIONAL check.  Likely to cause more harm than good.

Added ac/stdarg.h and updated liblber encode/decode to use it.