This patch corrects the issues from the AP_EXPORT and linkage

  This patch corrects the issues from the AP_EXPORT and linkage
  specification arguments to the ap_hooks.h declarations.  As with
  the APR_ and AP_ patches, API_VAR_EXPORT becomes API_EXPORT_VAR,
  and MODULE_VAR_EXPORT becomes MODULE_EXPORT_VAR.

  I will be happy to revert the inclusion of ap_config.h from
  httpd.h if this bothers anyone.  More individual modules need
  to be patched if we do so.

  The API_EXPORTs all moved into central storage in the ap_config.h
  header.  Without WIN32 or API_STATIC compile time declarations,
  these macros remain no-ops.

  This patch also moves the following data from http_main to http_config:

    const char *ap_server_argv0;
    const char *ap_server_root;
    ap_array_header_t *ap_server_pre_read_config;
    ap_array_header_t *ap_server_post_read_config;
    ap_array_header_t *ap_server_config_defines;

  And the following variables had already moved into ap_hooks.c:

    ap_pool_t *g_pHookPool;  (initialized now in http_config)
    int g_bDebugHooks;                   (out of http_config)
    const char *g_szCurrentHookName;     (out of http_config)

  The changes to http_main.c are in preparation for that module to
  move out to a seperate .exe for win32.  Other platforms will be
  unaffected, outside of these changes.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85309 13f79535-47bb-0310-9956-ffa450edef68