diff-mode misinterprets empty lines.

[Sergei Organov]

Hello,

In GNU Emacs 22.1.1 (i686-pc-linux-gnu, GTK+ Version 2.8.20).

GNU diff since version 2.8.7 outputs empty lines in the unified diff
format for empty context lines that don't change (instead of single
space followed by newline). See, e.g., the thread starting here:

<http://lists.gnu.org/archive/html/bug-gnu-utils/2006-09/msg00005.html>

Emacs diff-mode interprets empty lines as patch hunk separators, in
particular leading to wrong calculation of the length put into hunk
header. Another symptom is "C-c C-n" (diff-restrict-view) wrongly
restricts hunks with empty line(s).

Here is a patch hunk to test on:

@@ -1,7 +1,7 @@
 l1

 l3
-         abc
+         cba
 l5
 l6
 l7


-- 
Sergei Organov.