Fix --enable-layout processing on NetBSD. This makes us use a consistant

location for the config.layout file, and it makes us a bit more portable.
PR:     7482
Submitted by:   jun-ichiro hagino <itojun@iijlab.net>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88647 13f79535-47bb-0310-9956-ffa450edef68