Allow HTTPD_ROOT, SERVER_CONFIG_FILE, DEFAULT_PATH, and SHELL_PATH

to be configured via -D in Configuration.  PR#449

Reviewed by:	Roy


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@78059 13f79535-47bb-0310-9956-ffa450edef68