Add mat file with git lfs.

Closes #1853.

Ref. !2023

[skip ci]

In practice, for the time being, we limit ourselves to C++20 features available
in GCC 10.

They don’t bring any added value, and break compilation in C++20 mode (because
they are then of type “const char8_t *” which is distinct from “const char *”).

Closes: #1852

[skip ci]

Ref. !2022

Perfect foresight with expectation errors: move computation of terminal steady states to the setup command

This is more logical, since those values are constraints from the point of view
of the solver.

Also, this allows to have maxit and tolf options for the steady state solver,
at the level of the setup command, without a clash with the same option names
for the deterministic solver at the level of the solver command.

As a consequence, move the sanity checks inside evaluate_steady_state, where
they make more sense.

evaluate_steady_state.m: correctly account for presence of auxiliary variables potentially depending on Lagrange multipliers

Otherwise error message due to NaN may be thrown out due to them non having been set. Closes Dynare/preprocessor#94

Occbin: filter out problems in solving the baseline model

See merge request Dynare/dynare!2021

— Reject exogenous deterministic variables in a few places where they were
  erroneously accepted
– Use booleans for “exo_det” and “multiplicative” fields of M_.det_shocks
— Add checks on the value of the “learnt_in” option of “shocks” and “endval”

simult.m: fix saving of binary file

See merge request Dynare/dynare!2020

For use with perfect_foresight_with_expectation_errors_setup.

Call the wrapper instead of the dynamic routine.

– Improve messages during model normalization
– Macro-processor: more robust handling of empty files
– Improvements to macroprocessor slides

The feval(f, x, args{:}) call would fail under Octave because the contents of
args{:} would be appended twice (hence too many input arguments error).

The same bug would materialize under MATLAB for errorcode>1.