Unable to find LAPACKE symbols in libeigen_lapack.so

after finding correct blas.h and lapacke.h in eigen I get error at the last step that

undefined reference to `LAPACKE_dgetri'

and more like this. Is there a flag that I am missing or sth else? my build instructions

cmake -DCMAKE_INSTALL_PREFIX=/opt/eigen/ ..
make blas 
make lapack
make install

Thank you!