* nscd/nscd.h (prune_cache): Add fd argument to prototype.

* nscd/nscd.h (prune_cache): Add fd argument to prototype.

	* nscd/nscd.c (parse_opt): Read response from INVALIDATE request
	to make sure the database has been already invalidated.
	* nscd/cache.c (prune_cache): Add fd argument.  Write response to fd
	after the cache has been invalidated.  Use pthread_mutex_lock rather
	than pthread_mutex_trylock if fd != -1.
	* nscd/connections.c (invalidate_cache): Add fd argument, write
	response to fd if not calling prune_cache, pass fd to prune_cache.
	(handle_request): Adjust invalidate_cache caller.
	(nscd_run): Pass -1 as fd to prune_cache.