Although FEMLISP has an own implementation of the BLAS/LAPACK capabilities it needs, the optimized versions may increase performance significantly.
On Debian/GNU Linux, these libraries are available as packages called something like “libblas<version>” or “liblapack<version>”. These packages provide shared libraries (.so suffix) which are linked to FEMLISP when it is loaded.
It looks as if the developer packages “libblas-dev” and “liblapack-dev” provide “libblas.so” and “liblapack.so” without a version suffix, which are the default names tried by FEMLISP. So doing
sudo apt install libblas-dev liblapack-dev
might be the easiest way to make these routines available in FEMLISP.