Discovered in #321.  The number of argument for pa_rtpoll_run have
been changed since 6.0.

>=6.0 : int pa_rtpoll_run(pa_rtpoll *f);
<6.0  : int pa_rtpoll_run(pa_rtpoll *f, bool wait);

Check pulseaudio version by PA_CHECK_VERSION macro introduced since
pulseaudio 0.9.16.  In case PA_CHECK_VERSION is not defined,
pa_rtpoll_run takes 2 arguments.