We don't need the capability to build an acconfig.h anymore; AC_DEFINE

provides everything we need for equivalent functionality. This change
deletes the intrastructure that built acconfig.h.in before.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@84344 13f79535-47bb-0310-9956-ffa450edef68