bug#4451: 23.1; EOL problems with vc-diff and cygwin

[Reiner Steib]

Hi,

on Windows (with diff.exe from cygwin), I get annoying `^M' characters
in the diff output (see attached file vc-diff-2.output) when using
`C-x v =' (`vc-diff') on a file with Unix-style EOL.

[I now noticed that the attached file vc-diff-2.output has _two_ ^M at
each line ending.  I'm not sure if these were there already or 
if it happened during transport.  But it's unlikely because M$ Outlook
sent it base64 encoded.]

The `^M' charaters also break `C-c C-u' (`diff-context->unified').

When using `=' (`cvs-mode-diff') from PCL-CVS mode, there is no problem
(see attached file cvs-mode-diff.output).

Expected behavior: `vc-diff' should behave like `cvs-mode-diff' in this
case.

The file in question is K3.xml; "mode line" -> "describe coding
system" says:

| U -- utf-8-unix (alias: mule-utf-8-unix)
| 
| UTF-8 (no signature (BOM))
| Type: utf-8 (UTF-8: Emacs internal multibyte form)
| EOL type: LF
| This coding system encodes the following charsets:
|   unicode

More information about/from Emacs:

| ELISP> (executable-find "diff")
| "c:/P.../cygwin/bin/diff.exe"
| ELISP> (shell-command-to-string "diff --version")
| "diff (GNU diffutils) 2.8.7\nWritten [...]"
| ELISP>
| 
| In GNU Emacs 23.1.1 (i386-mingw-nt6.0.6001)
|  of 2009-07-30 on SOFT-MJASON
| Windowing system distributor `Microsoft Corp.', version 6.0.6001
| configured using `configure --with-gcc (4.4)'
| 
| 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: DEU
|   value of $XMODIFIERS: nil
|   locale-coding-system: cp1252
|   default-enable-multibyte-characters: t
| 
| Major mode: Diff
| 
| Minor modes in effect:
|   cvs-minor-mode: t
|   diff-auto-refine-mode: t
|   tooltip-mode: t
|   tool-bar-mode: t
|   mouse-wheel-mode: t
|   menu-bar-mode: t
|   file-name-shadow-mode: t
|   global-font-lock-mode: t
|   font-lock-mode: t
|   blink-cursor-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

Information about/from Cygwin:

| GNU bash, version 3.2.39(20)-release (i686-pc-cygwin)
| 
| $ file K3.xml 
| K3.xml: XML 1.0 document text
| $ file --version
| file-4.21
| magic file from /usr/share/file/magic
| 
| $ diff --version
| diff (GNU diffutils) 2.8.7
| $ grep diff ~/.cvsrc
| diff -u

Bye, Reiner

vc-diff-2.output
Description: Binary data

cvs-mode-diff.output
Description: Binary data