Make buildconf work with out-of-tree apr and apr-util by adding --with-apr

and --with-apr-util flags.

Submitted by:   Thom May <thom@planetarytramp.net>
Reviewed by:    Justin Erenkrantz (with minor stylistic nit)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@98546 13f79535-47bb-0310-9956-ffa450edef68