Merge branch 'js/git-gui-msgfmt-on-windows' into maint

Because recent Git for Windows do come with a real msgfmt, the
build procedure for git-gui has been updated to use it instead of a
hand-rolled substitute.

* js/git-gui-msgfmt-on-windows:
  git-gui (MinGW): make use of MSys2's msgfmt
  git gui: allow for a long recentrepo list
  git gui: de-dup selected repo from recentrepo history
  git gui: cope with duplicates in _get_recentrepo
  git-gui: remove duplicate entries from .gitconfig's gui.recentrepo