Do not use __ptr_t

[Joseph Myers]

On Tue, 8 Aug 2017, Paul Eggert wrote:

> Joseph Myers wrote:
> > Would you like to propose a patch (that deprecates __ptr_t like that
> 
> Sure, that's easy enough. Proposed patch attached.

OK (subject to testing on at least one platform), unless there are any 
objections within the next few days.  (But if distribution rebuilds show 
excessive fallout from this change - much more than you'd generally expect 
from a new GCC or glibc version - we may need to reconsider.)

-- 
Joseph S. Myers
joseph@codesourcery.com