dumping the keyring:

	% pksclient /foo/db since 0 [b]

	the "b" flag makes it produce binary output.

	the resulting file can be split up into smaller
	self-contained pgp keyrings using pgpsplit.

loading the keyring:

	% pksclient /foo/db add file.pgp

	the file can be either the direct output of the dump
	above, or one of the keyrings produced by pgpsplit.

what's using xfilecontents, as far as largefile support goes?

	mail_send.c:	small-volume mail stuff, don't care
	pks_socket.c:	mail stuff, don't care
	pksmailreq.c:	mail stuff, don't care

	pgpfile.c:	for pgpdump?  might care
	pgpsplit.c:	definitely care
	pksclient.c:	loading keyrings, definitely care