bug#23075: 24.5; vc-git-command should use coding-system-for-read

[Óscar Fuentes]

Eli Zaretskii <eliz@gnu.org> writes:

>> Does git always use that encoding? If not, on what it depends the
>> encoding used by git?
>
> It just spews the bytes, AFAIK.  IOW, it's the encoding of the file
> whose log we are viewing.

I was expecting from HELLO to be utf-8, but you are right.

Please note that a diff may contain changes from multiple files,
including some that do not longer exists (or that exists with another
encoding). So we can't process a diff as a single unit, it must be
separated by file.

Solving this on a general way does not seem possible, but we can do our
best by using the file's current encoding, or simply guessing it. The
former can have serious performance implications.