Fix for bug where DIRECTORY-FILES listed subdirectories.

  (defun directory-exists-p (x)

    "Is X the name of a directory that exists on the filesystem?"

    #+allegro

    (excl:probe-directory x)

    #-allegro

    (let ((p (probe-file* x :truename t)))

      (and (directory-pathname-p p) p)))

  (defun directory-files (directory &optional (pattern *wild-file*))

    "Return a list of the files in a directory according to the PATTERN,

which is not very portable to override. Try not resolve symlinks if implementation allows."

    "Return a list of the files in a directory according to the PATTERN.

Subdirectories should NOT be returned.

  PATTERN defaults to a pattern carefully chosen based on the implementation;

override the default at your own risk.

  DIRECTORY-FILES tries NOT to resolve symlinks if the implementation

permits this."

    (let ((dir (pathname directory)))

      (when (logical-pathname-p dir)

        ;; Because of the filtering we do below,

                              #+clisp

                              (when (equal :wild (pathname-type pattern))

                                (ignore-errors (directory* (make-pathname :type nil :defaults pat)))))))

        (remove-if 'directory-exists-p

                   (filter-logical-directory-results

                    directory entries

                    #'(lambda (f)

                        (make-pathname :defaults dir

                                       :name (make-pathname-component-logical (pathname-name f))

                                       :type (make-pathname-component-logical (pathname-type f))

                            :version (make-pathname-component-logical (pathname-version f))))))))

                                       :version (make-pathname-component-logical (pathname-version f)))))))))

  (defun subdirectories (directory)

    "Given a DIRECTORY pathname designator, return a list of the subdirectories under it."