Compilator can't find Eigen/Dense

[FromColleWithLove]

Hello,
I'm trying to compile Flare with Lammps.
I ran succesfully the install.sh from flare/lammps_plugins .

It is metioned that a workaround to have the Eigen libraries working is to copy the folder to lammps/src/

flare/lammps_plugins/README.md

Line 17 in 700f2c8

*Note: The pair style uses the [Eigen](https://gitlab.com/libeigen/eigen) (header-only) library. This needs to be found by the compiler. Specifically, the `Eigen` folder. A simple workaround is usually to just clone the `eigen` repository, and `mv eigen/Eigen /path/to/lammps/src/` if it is not easily available on your system.*

However, even after doing this, i still get this error:

In file included from ../lammps_descriptor.cpp:1:
../lammps_descriptor.h:4:10: fatal error: Eigen/Dense: No such file or directory
4 | #include <Eigen/Dense>
| ^~~~~~~~~~~~~
compilation terminated.

What might I do wrong? My makefile is modified but works with the normal compilation.
Not even the normal compilation
"make mpi" from "lammps/src"
works.

Am I missing something?

Thank you.

[FromColleWithLove]

Compiling with make, you must include the path to eigein in the LAMMPS'makefile.

Maybe this could be mentioned in https://mir-group.github.io/flare/installation/lammps.html