[cffi-devel] How can I teach cffi-features-p to test for :cygwin (or :windows)

Hello, I am running clisp on cygwin on windows. I am using a package that would like to maintain a distinction between cygwin and unix libraries in cffi:define-foreign-library (cygwin libraries are windows dll's). :cygwin is a member of *features* The package maintainer tried using the :cygwin feature, but cffi-feature-p does not capture it. I tried adding :cygwin to the list of exported features in features.lisp, but that did not work. I looked at the logic of cffi-features-p, but don't quite understand it. So, how is it possible to add :cygwin to the list of features to cffi-features? Thank you, Mirko