$ sudo apt-get update
$ sudo apt-get install gfortran-spu 

gfortran-spu is installed in your system.

Make ensure the gfortran-spu package were installed using the commands given below,

$ sudo dpkg-query -l | grep gfortran-spu *

You will get with gfortran-spu package name, version, architecture and description in a table

gfortran-spu package basic information: