For some reason the newest master can't seem to start subprocesses on
macOS:
emacs -batch -Q --eval='(call-process "/usr/bin/true")'
Searching for program: Is a directory, /usr/bin/true
Needless to say, /usr/bin/true is a regular file.
commit 327d251f8a857350a78029c31c7ab3f9797cc727
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat Feb 3 12:10:19 2018 -0800