Undefined vtable for TPython

Dear all,
i have a C++ class where i want to use TPython to execute a script with
TPython::ExecScript(“pippo.py”)
I have inlcuded TPyhton.h header and i get linking error undefined vtable for TPython. I can use any other ROOT classe without problem, using ROOT version 5.14.00h.
Can you please give me some hint ?

Thanks,
Max

i solved with an explicit link to PyROOT in the makefile.