Linking against Gtk3 version of libxfce4ui

[flo.xfce at gmx-topmail.de]

Hey everyone,
I'm working on porting xfce4-notifyd at the moment but I just can't test
it. It always links against libxfce4ui-1, which is the Gtk2 version on
my system, where libxfce4ui-2 is the Gtk3 version.
I changed the configure script to include
XDT_CHECK_PACKAGE([LIBXFCE4UI], [libxfce4ui-2], [4.12.0]), but this has
no effect.
No other gtk-depending lib is linked, I checked with ldd. The problem
lays with libxfce4ui.
Any hints?

Regards
Flo