- let cryptographic checksums refer to each other

- avoid .Xref to one's own manpage

src/lib/libc/hash/sha1.3

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sha1.3,v 1.16 1999/08/11 03:06:06 deraadt Exp $
+.\"	$OpenBSD: sha1.3,v 1.17 1999/10/06 14:55:29 espie Exp $
 .\"
 .\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 .\" All rights reserved.
@@ -197,7 +197,8 @@ helper functions are derived from code written by Poul-Henning Kamp.
 .Sh SEE ALSO
 .Xr sha1 1 ,
 .Xr md4 3 ,
-.Xr md5 3
+.Xr md5 3 ,
+.Xr rmd160 3
 .Pp
 .Rs
 .%A J. Burrows