Warn on attempted use of BUNDLE-OP where unsupported.

  (defun bundle-system (system &rest args &key force (verbose t) version &allow-other-keys)

    (declare (ignore force verbose version))

    (apply #'operate 'binary-op system args)))

#+(and (not asdf-use-unsafe-mac-bundle-op)

       (or (and ecl darwin) (and abcl darwin)))

(defmethod perform :before ((op bundle-op) c)

  (declare (ignorable op c))

  (unless (uiop:featurep :asdf-use-unsafe-mac-bundle-op)

    (cerror "Continue after modifying *FEATURES*."

            "The BUNDLE-OPs are not supported on Mac OSX for this lisp.~%~TTo continue, push :asdf-use-unsafe-mac-bundle-op on *FEATURES*.~%~TPlease report to ASDF-DEVEL if this works for you.")))