Add cgidir, htdocsdir, iconsdir variables to Makefile.tmpl in order

to make platform installations easier.

Submitted by:	Wilfredo Sanchez <wsanchez@apple.com>
Reviewed by:	Roy Fielding


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82880 13f79535-47bb-0310-9956-ffa450edef68