Subject: bug#21353: 25.0.50; Emacs Trunk (OSX) -- `default-directory` is initially set to "."

From: Eli Zaretskii <[email-masked]>
Date: Wed, 26 Aug 2015 20:12:28 +0300

> Date: Wed, 26 Aug 2015 09:39:25 -0700
> From: Keith David Bershatsky <[email-masked]>
> 
> The `default-directory` is initially set to "."

You mean, in the *scratch* buffer?  That happens in the function
init_buffer; we get the directory by calling get_current_dir_name.
Perhaps that function doesn't work well on Darwin?  Can you step with
a debugger through init_buffer, and see what happens there?