(rmail-simplified-subject): Normalize whitespace in subject. This

resurrects a feature, lost in transition to mbox, whereby Subject is
matched even if it's broken into several lines at arbitrary places.

lisp/ChangeLog

+2009-04-08  Eli Zaretskii  <eliz@gnu.org>
+
+	* mail/rmail.el (rmail-simplified-subject): Normalize whitespace
+	in subject.  This resurrects a feature, lost in transition to
+	mbox, whereby Subject is matched even if it's broken into several
+	lines at arbitrary places.
+
 2009-04-08  Nick Roberts  <nickrob@snap.net.nz>
 
 	* progmodes/gdb-ui.el: Give hint for GDB in Emacs on Mac OSX.

lisp/mail/rmail.el

@@ -3046,6 +3046,10 @@ and typical reply prefixes such as Re:."
 	(setq subject (substring subject (match-end 0))))
     (if (string-match "[ \t]+\\'" subject)
 	(setq subject (substring subject 0 (match-beginning 0))))
+    ;; If Subject is long, mailers will break it into several lines at
+    ;; arbitrary places, so normalize whitespace by replacing every
+    ;; run of whitespace characters with a single space.
+    (setq subject (replace-regexp-in-string "[ \t\n]+" " " subject))
     subject))
 
 (defun rmail-simplified-subject-regexp ()