spc in mailbox thing

[Simon Josefsson <jas@pdc.kth.se>]

Oh, and to make Gnus not discard mailboxes containing SPC as a invalid
newsgroup, you'll need this in your .gnus.

(setq gnus-ignored-newsgroups
      (mapconcat 'identity
         '("^to\\."
           "^[0-9. \t]+ "
           "[][#'()]"
           )
         "\\|"))

If you've modified `gnus-ignored-newsgroups' already, the thing that
differs is that I've removed `"' and you'll need to make that change
yourself.