For symmetry with the dynamic case, and for avoiding a call to “return” in the
middle of StaticModel::writeDriverOutput().

In particular, use a std::variant to store the values of options. This ensures
that a given option name can have only one value (previously, for a given
option name, it was possible to store several values as long as they were of
different types).

The local value of option was not copied to the top-level “options_” structure,
as it is done for “nograph” and “nodisplay”.

When computing the derivatives or block decomposition of the planner objective,
the epilogue or the original Ramsey model, the preprocessor would talk about
dynamic/static model, which was confusing. It now uses the right terminology.

If block decomposition fails, error out if “block” option was passed, but not
otherwise.

This commit does not modify the generated files.

This is a preliminary step for dynare#1859.

Add missing whitespace in output of BGP warning

See merge request !65

[skip ci]

Incidentally, make BytecodeInstruction an immutable struct, to facilitate
access to opcode in such a list.

[skip ci]

Ref. dynare#1856

Compute temporary terms for derivatives of “evaluate” mode, even though those
derivatives are not computed. This is because the temporary terms may be useful
for subsequent blocks.

By the way, add an explanatory comment for the equivalent code in dynamic file.

There were actually two distinct bugs, leading to incorrect results in some
corner cases:

– in the “evaluate” mode of the bytecode MEX, the temporary terms of the
  derivatives “evaluate” blocks were not evaluated at runtime; but these
  temporary terms may be needed for residuals of subsequent blocks;

– when the bytecode MEX was only computing residuals of the model (and not 1st
  order derivatives), the temporary terms of the derivatives were not evaluated
  at runtime; but these temporary terms may be needed for residuals of subsequent
  blocks.

It’s redundant with FBINARY{BinaryOpcode::plus}.

Rather make all data members public and const, and use aggregate-initialization.

By the way, turn those classes into structs since all their members are public.

The “temporary_terms_union.insert(it)” statement introduced in the previous
commit was in the wrong block.

By the way, replace the “switch” by an “if constexpr”.

Variable and parameter indices were wrong (offset by 1).

Confusion between a symbol ID and a derivation ID, which could lead to invalid
output or crash.

So that more stuff is computed at compile-time (using constexpr features).