* core: Fix -D[efined] or <Define>[d] variables lifetime accross restarts.

        PR 57328.

Submitted-by: Armin Abfalterer <a.abfalterer gmail.com>
Reviewed/Committed-by: ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1643825 13f79535-47bb-0310-9956-ffa450edef68