In the non-root mode, cmake complains that the library LAPACK can not be found, even if the external libraries have already been installed corrected. I found there is something wrong in the file 'itpp-4.3.1/cmake/Modules/FindLAPACK.cmake'.
On line 214, it is
set(_flags "gfortran;m")#needed by itpp-external
if we change it to
set(_flags "gfortran")#needed by itpp-external
then this problem can be solved.