+pcre (POSIX Regular Expression library):
+ftp://ftp.cus.cam.ac.uk/pub/software/programs/pcre/
+
+Most platforms do not required this. However older 4.3 BSD do not
+have a posix regex library.
+
+S/Key Libraries:
+http://www.sparc.spb.su/solaris/skey/
+
+If you wish to use --with-skey then you will need the above library
+installed. No other current S/Key library is currently known to be
+supported.
+