MFC r304911

MFC r304911

The formal behavior of qsort is unstable with regard to objects that
are equal. Unfortunately, RFC 3484 requires that otherwise equal objects
remain in the order supplied by the DNS server. The present code attempts
to deal with this by returning -1 for objects that are equal (i.e.,
returns that the first parameter is less then the second parameter).
Unfortunately, the qsort API does not state that the first parameter
passed in is in any particular position in the list.

PR:     212122
Submitted by:   Herbie.Robinson@stratus.com

git-svn-id: svn://svn.freebsd.org/base/stable/10@305037 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f