Added support for Berkeley-DB/3.x to mod_auth_db.

Submitted by: Steve Atkins <steve@blighty.com>
Cleaned up and reviewed by: Ralf S. Engelschall
PR: 5382


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@84175 13f79535-47bb-0310-9956-ffa450edef68