0.6.11.40:

0.6.11.40:
	added code to support coming changes in (probably) 0.6.11.41..
	..moving Unix opendir/readdir/closedir iteration down to the C
		level, so that all structure layouts and whatnot can be
		read directly from #include files, so that directory
		operations become inherently portable (or at least as
		much as C/Unix ever is:-) and work on OpenBSD
	..replacing old *UNIX-ERROR* cruft with STRERROR and
		SIMPLE-PERROR
	GET-ERRNO belongs in SB-C-CALL, it's not Unix-specific.