mingw32-git: Improve the comment about the Git version

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
mingw32-git: Split out doc and lic packages

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
mingw32-git: Add HTML docs

Get the auto-built HTML docs from the official git-htmldocs repository and
install them into MSYS' default location. The "html" makefile target is not
usable for us as it depends on unavailable AsciiDoc / Python programs.

Signed-off-by: Thomas Braun <thomas.braun@virtuell-zuhause.de>
Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
mingw32-git: Use dashes instead of dots in the version number suffix

Do this to be able to more easily separate our custom suffix from the
version number in Git's Makefile.

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>