bug#28412: 26.0.50; Let save-some-buffers accept write-contents-functions

[Eli Zaretskii]

> From: Kaushal Modi <kaushal.modi@gmail.com>
> Date: Mon, 18 Sep 2017 19:23:10 +0000
> Cc: 28412@debbugs.gnu.org
> 
> (string= (substring name 0 1) " ")
> 
> I was wondering if that should be wrapped into a function like 
> buffer-internal-p (based on the many docstrings
> like below in buff-menu.el: "By default, the Buffer Menu lists all buffers 
> except those whose names start with a
> space (which are for internal use)."). Having a function like this would be 
> better than having that logic
> implemented in different ways in the emacs core.
> 
> I just don't know the best place to put this function definition. Eli?

I'm not sure such a simple test should be canonicalized.