bug#3987: 23.1; Rmail summary missing dates when case-fold-search is nil

In GNU Emacs 23.1.1 (x86_64-unknown-linux-gnu, X toolkit)
 of 2009-07-30 on londo.cneufeld.ca
configured using `configure  '--prefix=/usr' '--with-x' '--with-xpm' 
'--with-jpeg' '--with-tiff' '--with-gif' '--with-png' '--enable-font-backend' 
'--with-xft' '--with-freetype' '--with-x-toolkit=lucid''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  value of $XMODIFIERS: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: RMAIL

Minor modes in effect:
  pc-selection-mode: t
  display-time-mode: t
  tooltip-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Loading rmailout...done
Loading sendmail...done
Loading mailalias...done
Loading supercite...done
Loading delsel...done
Loading pc-select...done
Counting messages...done
(No new mail has arrived)
0 new messages read
Computing summary lines...done


Some time between 23.0.60 and 23.1, a minor annoyance was introduced into
rmail.  When case-fold-search is nil, the dates in the rmail summary are
all rendered as "??????".

This is because of the regular expression in rmailsum.el at line 529.  A
string such as "May" doesn't match the regular expression:
[adfjmnos][acepou][bcglnprtvy]

because the capital letter doesn't match when case-fold-search is nil.

The easy work-around is to turn on case-fold-search, but it would be nice
to fix it properly, so that rmail works no matter what the user-set value
is.  It may also be useful to do a quick scan of the .el files to see if
there are other cases where a nil value of case-fold-search might break
some modes or behaviours.


-- 
 Christopher Neufeld
 Home page:  http://www.cneufeld.ca/neufeld
 "Don't edit reality for the sake of simplicity"