xfce4-mixer-4.4.3 broken

[Christoph Wickert]

A bug was introduced in xfce4-mixer-4.4.3 that renders the panel plugin
unusable: Even if you configure xfce4-mixer with "--prefix=/usr" 
/usr/share/xfce4/panel-plugins/xfce4-mixer.desktop will have
X-XFCE-Exec=/usr/local/libexec/xfce4/panel-plugins/xfce4-mixer-plugin
                ^^^^^^
Why is prefix not picked up properly? This used to work in 4.4.2

Christoph