emacs-repository-version on MS-Windows

[Eli Zaretskii]

Would people who build the development sources from the master branch
of the git repository please check that their emacs-repository-version
value is non-nil?

There is some subtle issue with invoking git on Windows from temacs,
which prevented it from working on my machine.  I fixed it by local
changes to the way git is invoked by Emacs, but I wonder whether it's
only my local problem.