Add optional hook to extend mod_status output.

* configure.in: Add modules/generators to include path.

* Makefile.in: Install mod_status.h.

* modules/generators/mod_status.h: New file.

* modules/generators/mod_status.c: Implement ap_run_status_hook.
(status_handler): Run status hooks.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@100724 13f79535-47bb-0310-9956-ffa450edef68