UpnpInit fails when process cannot alter its own scheduling

The ThreadPool management attempts to call sched_setscheduler() and pthread_setschedparam(), in order to set the thread scheduling priorities for the tasks in its various pools. It returns an error if the scheduling calls fail.

These calls do indeed fail with EPERM when running as non-root on FreeBSD (and, apparently, on Gnu Hurd although I don't have an installation of that one). According to POSIX it is implementation defined as to whether a process may be allowed to alter its own scheduling priorities and parameters. Linux apparently allows it; the others don't.

The result of this is that libupnp will only run as root on FreeBSD and cannot be used by a user application.

Quick way to test this is to do a "make check" as a non-root user, which will fail if the calls are not permitted.

I'm working on a patch to assume a good result if the scheduler calls return EPERM. It seems to me that, in this case, we will just fall back to our own three priority pools. Does this sound an OK workaround ?