bipedal-locomotion-framework: CppADTest fails to comple

I’ve just install a clean ubuntu 20.04 distro on my pc. I installed catch2 and the superbuild.

When I enabled the tests in blf I got the following error. The other tests compile (and run) without issues.

[ 66%] Building CXX object src/AutoDiff/tests/CMakeFiles/CppADTestUnitTests.dir/CppADTest.cpp.o
In file included from /home/gromualdi/robot-code/robotology-superbuild/src/bipedal-locomotion-framework/src/AutoDiff/tests/CppADTest.cpp:11:
/home/gromualdi/robot-code/robotology-superbuild/src/bipedal-locomotion-framework/src/AutoDiff/include/BipedalLocomotion/AutoDiff/CppAD.h:12:10: fatal error: cppad/cppad.hpp: No such file or directory
   12 | #include <cppad/cppad.hpp>
      |          ^~~~~~~~~~~~~~~~~
compilation terminated.