Investigate meson deprecation warning

[jared321]

I see the following in GH action logs

 frescox| DEPRECATION: Variable substitution with boolean value 'found_mpi' is deprecated.
 frescox| DEPRECATION: Variable substitution with boolean value 'found_openmp' is deprecated.
 frescox| DEPRECATION: Variable substitution with boolean value 'found_lapack' is deprecated.
 frescox| DEPRECATION: Variable substitution with boolean value 'use_corex' is deprecated.