Eli Zaretskii wrote:
>> Should be doable. I assume this would be for 'master', not 'emacs-26'?
> Yes, I think so.  Unless the original bug is extremely annoying and
> cannot wait, that is.

I installed the attached into master, as I guess the original bug is merely 
mildly annoying. We can backport it to emacs-26 if I guessed wrong. As this 
should fix the bug I'm boldly marking it as done.

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). That is lower priority, though.