[xfce4-panel] does not compile under cygwin

[Jasper Huijsmans]

SJM Arts schreef:
...
> Yes, but there is one more thing that needs to be done to get the
> plugins to compile. The .def file is missing from $(datadir)/xfce4/devel/.

Ehm, if I remember correctly the .def file was used to inform plugins 
about symbols in the panel executable that were used by the plugins, is 
that correct? There are no such symbols in the current panel, everything 
the plugins need is in the library.

	Jasper