bug#18360: Modularize recent qsort_r additions

[Eli Zaretskii]

> Date: Sat, 30 Aug 2014 06:44:43 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: 18360@debbugs.gnu.org
> 
> Eli Zaretskii wrote:
> > qsort is good enough for us for now.
> 
> Unfortunately qsort doesn't work either, as discussed in Bug#18361.

That is a different issue, and should not get in our way here.  For
the purposes of this bug, can we agree that qsort_r is not needed, and
the changes that use it should be reverted to use qsort instead?

We could then discuss separately what to do with qsort.