Note that the variable HAVE_DUNE_BOOST is not set by FindBoost, but by OpmAliases.
Note that the variable HAVE_UMFPACK is not set by FindSuiteSparse, but by OpmAliases.
Headers from other libraries (notably DUNE) require definitions of other variables than our probe process set (e.g. HAVE_UMFPACK instead of HAVE_SUITESPARSE_UMFPACK_H). This module sets those aliases for compatibility.