-Please don't require the @code{cl} package of Common Lisp extensions at
-run time. Use of this package is optional, and it is not part of the
-standard Emacs namespace. If your package loads @code{cl} at run time,
-that could cause name clashes for users who don't use that package.
-
-However, there is no problem with using the @code{cl} package at
-compile time, with @code{(eval-when-compile (require 'cl))}. That's
+If you need Common Lisp extensions, use the @code{cl-lib} library
+rather than the old @code{cl} library. The latter does not
+use a clean namespace (i.e., its definitions do not
+start with a @samp{cl-} prefix). If your package loads @code{cl} at
+run time, that could cause name clashes for users who don't use that
+package.
+
+There is no problem with using the @code{cl} package at @emph{compile}
+time, with @code{(eval-when-compile (require 'cl))}. That's