site-packages

Not everything is in MELPA or similar, so we also need a way to add local stuff
to =load-path=. This walks over =site-packages= and adds each directory in it.
#+BEGIN_SRC emacs-lisp
  (let ((default-directory
          (expand-file-name "site-packages" user-emacs-directory))
        (local-pkgs nil))
    (dolist (file (directory-files default-directory))
      (and (file-directory-p file)
           (string-match "\\`[[:alnum:]]" file)
           (setq local-pkgs (cons file local-pkgs))))
    (normal-top-level-add-to-load-path local-pkgs))
#+END_SRC