Reviewed by: Marc Slemko, Roy T. Fielding

Submitted by:	Brian Behlendorf

Needed prototype for ap_vsnprintf, and that needed varargs.h for va_list.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@77483 13f79535-47bb-0310-9956-ffa450edef68