Include apr_lib.h for the definition of apr_toupper() to get rid of

undefined symbol link failures (apr_toupper is a macro, at least on
Unix).

Reported by:  Trawick's regression build


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@95878 13f79535-47bb-0310-9956-ffa450edef68