We need to pass the prefix to APR, APR-util, and PCRE. If we don't

pass that information, then all three libraries will install themselves
into their default locations.
PR:	7750


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89515 13f79535-47bb-0310-9956-ffa450edef68