bug#23076: 24.5; vc-git: add a new variable for log output coding system

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 04 Apr 2016 18:22:30 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 23076@debbugs.gnu.org
> 
> So instead, I can suggest one of the following alternatives, to be
> done only when invoking Git to commit on MS-Windows:
> 
>  1) ignore vc-git-commits-coding-system and always encode the
>     command-line arguments using the system locale (in your case,
>     codepage 1251); or
> 
>  2) put the log message in a temporary file, encoded in
>     vc-git-commits-coding-system, then use -F instead of -m; the rest
>     of command-line arguments will be encoded in the system locale's
>     codepage
> 
> The 1st solution is essentially what you wanted, but without the need
> to introduce an additional variable or ask the users to configure it.
> 
> The 2nd solution is somewhat slower, but it is better, because it will
> allow to write log messages using any characters, not just those
> representable in the current codepage.  Note that it still doesn't
> solve all the problems with non-ASCII characters, because those could
> be in the "author" or any of the other arguments with which we call
> Git, such as the names of the files whose changes are to be committed
> (as Emacs does support arbitrary characters in file names).
> 
> Comments?

Ping!