* nnshimbun.el (nnshimbun-retrieve-headers-with-nov): Don't use `last'.

* nnshimbun.el (nnshimbun-retrieve-headers-with-nov): Don't use `last'.
(nnshimbun-make-shimbun-header): Use the following macros.
(nnshimbun-mail-header-from): New macro whose definition will be changed
 statically for Gnus or gnus.
(nnshimbun-mail-header-subject): Ditto.
(TopLevel): Don't require `gnus-clfns'.

* gnus.el: Add autoload for `find-cl-run-time-functions'.

* gnus-clfns.el (find-cl-run-time-functions): New command for the developers.
(cl-run-time-functions): New variable.
(TopLevel): Don't require `cl' at run-time.