--- ssh2/configure.ac	2015-02-24 10:09:30.662277334 +0100
+++ ssh2/configure.ac.new	2015-02-24 10:08:57.658394756 +0100
@@ -133,6 +133,7 @@
     AC_MSG_NOTICE([Try --with-libz-prefix=PATH if you know you have it])
   else
     AC_DEFINE(LIBSSH2_HAVE_ZLIB, 1, [Compile in zlib support])
+    LIBS="$LIBS -lz"
   fi
 fi