I think hippo might be right, that Net::SSLeay isn't necessary. Observe:
steve@cecilia ~/scratch $ perl -v
This is perl 5, version 34, subversion 0 (v5.34.0) built for darwin-2l
+evel
cpanm FFI::Platypus output:
steve@cecilia ~/scratch $ cpanm FFI::Platypus
--> Working on FFI::Platypus
Fetching http://www.cpan.org/authors/id/P/PL/PLICEASE/FFI-Platypus-1.5
+3.tar.gz ... OK
Configuring FFI-Platypus-1.53 ... OK
==> Found dependencies: FFI::CheckLib, Alien::FFI, Test2::V0
... snipped for brevity ...
Successfully installed FFI-Platypus-1.53
16 distributions installed