currently I am trying to build vxl with shared libraries. So far
it looks like vxl is not set up to produce dll's. There seem to be
the following options:

- produce .def files like it was done in TargetJr (at the moment I don't know how one does this using cmake)

- work with 

This is how the problem is solved in vtk. They basically define a macro which is then used in every class definition.
When working on other platforms the macro is left blank.

It would be great if someone has already solved the problem or

has any suggestions,