bug#42836: 27.1; default-directory is set to "/" after startup

[Sean Devlin]

Hi Paul,

> Does the attached patch work for you? If so, I can install it into the 
> emacs-27 branch. (I don't use macOS so can't easily test it myself.)
> <0001-Fix-startup-working-dir-bug-on-NeXTSTEP.patch>

I tried the patch, and it does seem to work based on very limited testing. I 
should also add the caveat that I’m not experienced at building Emacs from 
source, so please take my testing with a grain of salt.

Thanks!