Could you please explain that in more detail?

I already build the qwt library, and the test examples included do also work.
Howerver as soon as I try to include QWT code in my project the errors shown above occur.
Moreover usual Qt code does also work. Is it probably necessary to add additional code in the .cmake file to add qwt as well?

Maybe you can tell me what else needs to be done, or where I can find closer Information.

Thanks and Regards