From the build log the original poster showed, this is on Windows?
There you have to define symbols to be exported/imported if you use them from a dll (__declspec(dllexport) / __declspec(dllimport). If you can build with shared libraries, it means that you have this in place (unless you use a .def file or use CMake’s automated way of creating it ).
If you still have these declarations in place when trying to compile and link the library statically however, you might get those errors you mention I think