ITS#5364, thread pool efficiency:

Add ldap_pvt_thread_pool_pausing(): pause check for slapd without locking.

include/ldap_pvt_thread.h

@@ -243,6 +243,10 @@ ldap_pvt_thread_pool_query LDAP_P((
 	ldap_pvt_thread_pool_t *pool,
 	ldap_pvt_thread_pool_param_t param, void *value ));
 
+LDAP_F( int )
+ldap_pvt_thread_pool_pausing LDAP_P((
+	ldap_pvt_thread_pool_t *pool ));
+
 LDAP_F( int )
 ldap_pvt_thread_pool_backload LDAP_P((
 	ldap_pvt_thread_pool_t *pool ));