libxfce4ui is installed under /usr/include/libxfce4ui-1.0 by default, instead it should be installed as other Xfce libs under /usr/include/xfce4.
So?
So jsut do it like the other xfce libs. No? libxfce4ui is the only single lib that installs outside of the directory.
Do we care about this? Exo is also installed in $includedir. I don't have any problems changing this, but I doubt other desktops do this, so no strong opinion here.
Doesn't really matter to me. exo is sorta a "not really xfce" library, hence the difference. Yeah, by convention we put our stuff in /xfce4/, but there's no real reason for it, I don't think.
Fixed.