To install this package, run in Emacs:
M-x package-install RET cl-lib RET
This is a forward compatibility package, which provides (a subset of) the features of the cl-lib package introduced in Emacs-24.3, for use on previous emacsen (it should work on Emacs≥21 as well as XEmacs). Make sure this is installed *late* in your `load-path`, i.e. after Emacs's built-in .../lisp/emacs-lisp directory, so that if/when you upgrade to Emacs-24.3, the built-in version of the file will take precedence, otherwise you could get into trouble (although we try to hack our way around the problem in case it happens). This code is largely copied from Emacs-24.3's cl.el, with the alias bindings simply reversed.