Hi.

On Tue, 6 Feb 2018, at 09:08, Philipp Stephani wrote:
>> I see a breakage of Emacs build on master under MacOS 10.13. Build
>> stops with the following message:>> 
>> org/org-timer.el:39:1:Error: Searching for program: Is a directory,
>> /bin/zsh>> 
>> The file in question is not a directory:
>> 
>> % ls -l /bin/zsh
>> 404K -rwxr-xr-x 1 root wheel 596K
> This is https://debbugs.gnu.org/cgi/bugreport.cgi?bug=30350.

Yes, it is. I can't find the relevant sources right away, but opening a
file inside a file is a syntax for opening  resource forks under OS X,
so `/foo/bar/baz/.` is a "directory" of resource forks there. This
syntax is not likely to go away anytime soon.
Mikhail.