diff-hunk-header-re-unified does not match all hunks

[Bernhard Herzog <bh@intevation.de>]

diff-mode.el in CVS HEAD has an incorrect value for
diff-hunk-header-re-unified:

(defconst diff-hunk-header-re-unified
  "^@@ -\\([0-9]+\\)\\(?:,\\([0-9]+\\)\\)? \\+\\([0-9]+\\)\\(?:,\\([0-9]+\\)\\) @@")

There should be a '?' after the last group:

"^@@ -\\([0-9]+\\)\\(?:,\\([0-9]+\\)\\)? \\+\\([0-9]+\\)\\(?:,\\([0-9]+\\)\\)? @@"

As is, diff mode cannot deal properly with diffs like this:

diff -ruN origdir/newfile newdir/newfile
--- origdir/newfile	1970-01-01 01:00:00.000000000 +0100
+++ newdir/newfile	2008-04-24 10:47:53.661124659 +0200
@@ -0,0 +1 @@
+new file with a single line
diff -ruN origdir/some-file newdir/some-file
--- origdir/some-file	2008-04-24 10:54:52.930269418 +0200
+++ newdir/some-file	2008-04-24 10:55:12.147053567 +0200
@@ -1 +1 @@
-`Twas brillig, and the slithy toves
+did gyre and gimble in the wabe:


Navigating with diff-file-prev or diff-file-next does not find these
hunks.

   Bernhard

-- 
Bernhard Herzog                              Intevation GmbH, Osnabrück
Amtsgericht Osnabrück, HR B 18998             http://www.intevation.de/
Geschäftsführer: Frank Koormann, Bernhard Reiter, Dr. Jan-Oliver Wagner