mpm/prefork/prefork.c implements ap_graceful_stop_signalled() as
the following (BTW, same goes true for mpm/netware/mpm_netware.c but
I don't use that at all):

    int ap_graceful_stop_signalled(void)
    {
        /* not ever called anymore... */
        return 0;
    }
 
Not only the comment is wrong (the function IS actually called from
modules/core/http_core.c), this "implemetation" goes out of
sync with implementations of the same call in all other MPMs, so
any code that depends on whether the restart is graceful or
forced, will fail to detect this, yet the fix is the simplest ever:
just a return of "is_graceful" instead of plain "0" will do the job.