[patch] Fix BZ #18660 -- overflow in getusershell

[Tobias Stöckmann]

> On August 17, 2015 at 5:48 PM Joseph Myers <joseph@codesourcery.com> wrote:
> It's smaller than statb.st_size / 3 * sizeof (char *) (or the new adjusted 
> version thereof), since sizeof (char *) is 4 or 8 for configurations 
> supported by glibc.

I wonder what makes me blind towards "sizeof (char *)" these days.
You are right, of course.