You will need working installations of Zlib and OpenSSL.
-Zlib 1.1.4 or greater:
+Zlib 1.1.4 or 1.2.1.2 or greater (ealier 1.2.x versions have problems):
http://www.gzip.org/zlib/
OpenSSL 0.9.6 or greater:
S/Key Libraries:
-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.
+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/