RMUL2025/lib/eigen/demos/mix_eigen_and_c

This is an example of how one can wrap some of Eigen into a C library.

To try this with GCC, do:

  g++ -c binary_library.cpp -O2 -msse2 -I ../..
  gcc example.c binary_library.o -o example -lstdc++
  ./example

TODO: add CMakeLists, add more explanations here