Change the ap_assert macro to a variant that works on all platforms.

PR: 2575
Submitted by:	Richard Prinz <richard.prinz@cso.net>
Reviewed by:	Roy Fielding, Dirk-Willem van Gulik


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82584 13f79535-47bb-0310-9956-ffa450edef68