x11-toolkits/libxfce4gui, print/xfce4-print, and pkg_libchk

[Warren Block]

For the last few weeks, pkg_libchk from sysutils/bsdadminscripts has 
complained about libxfce4gui and xfce4-print:

% pkg_libchk
libxfce4gui-4.10.0_3: /usr/local/lib/libglade/2.0/libxfce4.so misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/bin/xfprint-settings misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/bin/xfprint-settings misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/bin/xfprint4 misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/bin/xfprint4 misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/bin/xfprint4-manager misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/bin/xfprint4-manager misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/lib/libxfprint.so.0.0.1 misses libxfcegui4.so.4
xfce4-print-4.6.1_12: /usr/local/lib/xfce4/xfprint-plugins/bsdlpr_plugin.so misses libxfcegui4.so.4

Rebuilding shows this is a false positive, but I'm curious why this 
started to happen and what can be done to fix it.

Incidentally, I run pkg_libchk -qo routinely after port upgrades now. 
It helps to avoid problems when versions aren't bumped or when the ports 
tree has been updated just before a version bump.