Correct module lookup when including ffi-module

[danielevans]

The inclusion of @ioquatix's ffi-module gem to a project causes errors loading other ffi gems (such as rbnacl) due to the definition of FFI::Module which makes .kind_of?(Module) equivalent to .kind_of?(FFI::Module).

This change simply changes that lookup to ensure that it is checking against the top-level Module constant.

[ioquatix]

Hmm, I wonder if I should rename the gem. I didn't realise this issue at the time.

[eregon]

The change is fine (make the check a bit more robust) but IMHO the much bigger issue is to define a class or module named Module which isn't the ::Module of Ruby core.
So +1000 to rename FFI::Module to something else.

[ioquatix]

FFI::SomethingElse

But seriously, I agree, this was kind of an oversight on my part.

That being said, I've encountered this issue in other places.

Sometimes Ruby constant lookup causes pain if someone introduces a new module into an existing one.

[larskanis]

Do we need a new release due to this issue?

[danielevans]

There is no rush to release the fix from my perspective, the issue is easily worked around and the ffi-module gem is not widely depended upon.