For supported versions of Darwin, place dynamically loaded

Apache extensions' public symbols into the global symbol
table. This allows dynamically loaded PHP extensions.
NOTE: this works as long as multiple modules don't
include overlapping symbols. Jim added the wrapper to
check for the existance of the option (which doesn't
exist in Rhapsody).

PR:
Obtained from:
Submitted by:	Marko Karppinen <markonen@php.net>
Reviewed by:	Jim Jagielski, Wilfredo Sanchez


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@94753 13f79535-47bb-0310-9956-ffa450edef68