+http://www.jmknoble.net/software/x11-ssh-askpass/
+
+TCP Wrappers:
+
+If you wish to use the TCP wrappers functionality you will need at least
+tcpd.h and libwrap.a, either in the standard include and library paths,
+or in the directory specified by --with-tcp-wrappers. Version 7.6 is
+known to work.
+
+http://ftp.porcupine.org/pub/security/index.html
+
+S/Key Libraries:
+
+If you wish to use --with-skey then you will need the library below
+installed. No other S/Key library is currently known to be supported.
+
+http://www.sparc.spb.su/solaris/skey/
+
+LibEdit:
+
+sftp supports command-line editing via NetBSD's libedit. If your platform
+has it available natively you can use that, alternatively you might try
+these multi-platform ports:
+
+http://www.thrysoee.dk/editline/
+http://sourceforge.net/projects/libedit/
+
+Autoconf:
+
+If you modify configure.ac or configure doesn't exist (eg if you checked
+the code out of CVS yourself) then you will need autoconf-2.61 to rebuild
+the automatically generated files by running "autoreconf". Earlier
+versions may also work but this is not guaranteed.
+
+http://www.gnu.org/software/autoconf/
+
+Basic Security Module (BSM):
+
+Native BSM support is know to exist in Solaris from at least 2.5.1,
+FreeBSD 6.1 and OS X. Alternatively, you may use the OpenBSM
+implementation (http://www.openbsm.org).