Prevent a compile warning on FreeBSD by making pointers const (only needed

for data, but not harmful for functions)

old warning: "exports.c:59: warning: initialization discards `const' from pointer target type"


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86784 13f79535-47bb-0310-9956-ffa450edef68