Allow Gnus to be an offline newsreader.
The gnus-agentize function is now called internally by gnus when
gnus-agent is set. If you wish to avoid calling gnus-agentize,
customize gnus-agent to nil.
This will modify the `gnus-setup-news-hook', and
`message-send-mail-real-function' variables, and install the Gnus agent
minor mode in all Gnus buffers.
(fn)