Makefile.PL comes with LIBS => q{-lz -lssl -lcrypto -lssl32 -lssleay32 -leay32})

If those libraries are not located at the 'perl Makefile.PL' step, they don't get written in to the generated Makefile.
It would seem that /usr/sfw/lib/64 is not being searched - for which another fix would be to change the quoted entry in the Makefile.PL to:

LIBS => [q{-lz -L/usr/sfw/lib/64 -lssl -lcrypto -lssl32 -lssleay32 -le
+ay32}])
[download]

Passing it through 'o conf' is probably a better solution - in that it doesn't involve manual editing of any files.
Yet another option would be to add /usr/sfw/lib/64 to the LIBRARY_PATH environment variable:

export LIBRARY_PATH=$LIBRARY_PATH:/usr/sfw/lib/64
[download]

Cheers,
Rob