bug#28639: 26.0.60; get-free-disk-space gives wrong number on OS X 10.8 and later

[Eli Zaretskii]

> Cc: mituharu@math.s.chiba-u.ac.jp, 28639-done@debbugs.gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sun, 1 Oct 2017 22:50:20 -0700
> 
> It strikes me that Emacs's support for fsusage on Microsoft platforms should 
> be 
> migrated into Gnulib, so that the support could benefit non-Emacs programs 
> like 
> GNU 'df' (and also simplify Emacs proper).

Indeed, I was surprised to see that Gnulib didn't support MS-Windows
in that module.

Thanks.