Remove GTK2 leftovers
It seems that these cause install performed twice causing natsy races - see [1] and search for 'TOPDIR/build/tmpfs/hosttools/install -c -m 644 ../../libxfce4ui-4.16.0/libxfce4ui/libxfce4ui.h'
[1] https://errors.yoctoproject.org/Errors/Details/540832/
Signed-off-by: Andreas Müller schnitzeltony@gmail.com