* nscd/aicache.c (addhstaiX): Check herrno after IPv4 lookup only

* nscd/aicache.c (addhstaiX): Check herrno after IPv4 lookup only

	when the lookup call failed.

	* nscd/nscd.h (struct database_dyn): Rename prunelock to prune_lock.
	Add prune_cond and wakeup_time.
	(CACHE_PRUNE_INTERNAL): Define.
	Update declarations of prune_cache and setup_thread.
	* nscd/connections.c (dbs): Update initializers.
	(CACHE_PRUNE_INTERNAL): Moved to nscd.h.
	(nscd_init): Default number of threads is now 4.
	(invalidate_cache): Take lock before calling prune_cache.
	(handle_request): If SELinux forbids the request, say so.
	(readylist_cond): Use static initializer.
	(nscd_run_prune): New function.  Used only by pruning threads.
	(nscd_run_worder): Renamed from nscd_run.  Remove support for pruning
	here.
	(fd_ready): Update nscd_run reference.
	(start_threads): No need to initialize readylist_cond.
	Start pruning threads separately.
	* nscd/nscd_setup_thread.c: Change return value type to int and always
	return 0.
	* sysdeps/unix/sysv/linux/nscd_setup_thread.c: Change return value type
	to int and return nonzero value if we can use the TID address hack.
	* nscd/cache.c (cache_add): If next wakeup time of cleanup thread for
	the database is later than the new entry's timeout, update the
	wakeup time and wake the cleanup thread.
	(prune_cache): Return seconds the next entry in the database is still
	valid.  Remove locking for pruning here.
	* nscd/nscd.conf: Document default number of threads.