This fixes the bug in my last commit. Apache always caches a value for

enable-threads.  This allows us to re-configure the server for different
MPM's without worrying about not having APR-threads available.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@84360 13f79535-47bb-0310-9956-ffa450edef68