Comment 31 for bug 668671

(In reply to comment #22)
> In both scenarios pulseaudio is not activated, just installed.
>
> So it is not vlc backend related, but seems like pulseaudio is the root of
> problem here for sure.

That makes sense as in order for the pulseaudio client application to test to see whether a server is running, the PA client application must check PA's configuration directives to see where to try and connect.

In your case this will ultimately result in the "PA is not running" scenario, and carry about it's business, but to get that far the X11 libraries have to be loaded (as PA configuration can be stored in X11 properties of the root X window to allow for seamless SSHing to remote machines and running audio producing applications remotely, but still seeing and hearing your application locally).

I pretty strongly suspect that the patch I linked above would address this issue by using the thread-safe XCB in PA rather than Xlib.

Note that calling XlibInitThreads (or whatever the API call is really called!) prior to all this should also work around this issue but this is sometimes awkward to do in client applications when an abstraction layer like phoon+engine is used.