This patch is sure to break someone!

This patch is sure to break someone!
We need to define MODULE_VAR_EXPORT, API_EXPORT, API_VAR_EXPORT, et. al.
in an os specific way and the definitions need to be done as soon as possible
in the include file chain. I choose to use os.h as the preferred mechanism
for doing this (for now anyway) since this is they way it was done for
Apache 1.3. win32/os.h and unix/os.h probably have some Apache private macro
definitions that are being exposed publicly because of this patch. The solution
to this problem is to remove the private definitions from os.h.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@84551 13f79535-47bb-0310-9956-ffa450edef68