The Git distributed revision control system was updated to version 2.12.0, which
brings several fixes and enhancements.

- Use of an empty string that is used for 'everything matches' is still warned and Git
asks users to use a more explicit '.' for that instead. In the future this warning
will be turned into a hard error.
- The historical argument order "git merge 'msg' HEAD 'commit'..." has been deprecated
for quite some time, and will be removed in a future release.
- An ancient script "git relink" has been removed.
- The character width table has been updated to match Unicode 9.0.