pavucontrol needs pulseaudio to be build with glib support
opt/pulseaudio does not automatically include this.
You need to do the following steps to build pavucontrol if pulseaudio
was not compiled against glib:

```
sudo ports -u
sudo prt-get depinst glib
sudo prt-get update -fr pulseaudio
sudo prt-get depinst pavucontrol
```