bug#12632: file permissions checking mishandled when setuid

[Paul Eggert]

On 10/14/2012 01:53 PM, Eli Zaretskii wrote:
> That sounds like a very weak reason to switch to a non-portable API

Since the main objection here seems to be using the non-portable
function euidaccess, I changed the patch to use faccessat instead.
faccessat, unlike euidaccess, is standardized by POSIX; it's a tad
more-complicated to use but it is standard and it's no doubt
a better solution in the long run anyway.  The patch
uses the Gnulib substitute for faccessat for obsolescent POSIXish
hosts that lack faccessat.  For Windows the patch simply reworks the
existing substitute for 'access' so that it implements faccessat instead.

Revised patch attached.

faccessat.txt
Description: Text document