  An extension of the relativistic density functional approach to the equation
of state for strongly interacting matter is suggested which generalizes a
recently developed modified excluded-volume mechanism to the case of
temperature and density dependent available-volume fractions. A parametrisation
of this dependence is presented for which at low temperatures and
suprasaturation densities a first-order phase transition is obtained. It
changes for increasing temperatures to a crossover transition via a critical
endpoint. This provides a benchmark case for studies of the role of such a
point in hydrodynamic simulations of ultrarelativistic heavy-ion collisions.
The approach is thermodynamically consistent and extendable to finite isospin
asymmetries that are relevant for simulations of neutron stars, their mergers
and core-collapse supernova explosions.
