On 01/19/2018 12:53 PM, Stefan Monnier wrote:
> which seems to me to be the result of an oversight: the original coder
> probably didn't realize that such a call would either create the temp
> file in the same directory as target-file or under /tmp depending on
> whether target-file is relative or absolute.

Right you are. (The "original coder" was me; sorry about that.) Since I 
broke it, I fixed it by installing the attached into emacs-26.