Sorry, it's not an error, it is just that he now runs perl 5.30 via perlbrew and compiles it with that (Re^6: XS.c: loadable library and perl binaries are mismatched (got handshake key 0xc100000, needed 0xc180000)). So yes, perhaps starting fresh from the beginning to see a) how it is compiled using the new settings (for example to confirm if correct binaries and library paths are used), b) where it fails if it does, c) strace output filtering out noise to see the fullpath of the library failing the handshake.