* gnus-util.el (gnus-bind-print-variables): New macro.
(gnus-prin1): Use it.
(gnus-prin1-to-string): Use it.
(gnus-pp): New function.
(gnus-pp-to-string): New function.
* gnus-cus.el (gnus-agent-cat-prepare-category-field): Replace pp-to-string
with gnus-pp-to-string.
* gnus-eform.el (gnus-edit-form): Replace pp with gnus-pp.
* gnus-group.el (gnus-group-make-kiboze-group): Ditto.
* gnus-msg.el (gnus-debug): Ditto.
* gnus-score.el (gnus-score-save): Ditto.
* gnus-spec.el (gnus-update-format): Replace pp-to-string with
gnus-pp-to-string.
* legacy-gnus-agent.el (gnus-agent-unlist-expire-days): Replace pp with
gnus-pp.
* score-mode.el (gnus-score-pretty-print): Ditto.
* webmail.el (webmail-debug): Ditto.