As a consequence, remove the --enable-openmp option of the configure script.

Testing shows that it is slower than the BLAS path.

It constructs the stacked residuals and jacobian of the perfect foresight
problem.

It is an almost perfect replacement for the perfect_foresight_problem.m
routine, while being much more efficient.

Note however that the DLL never return complex numbers (it instead puts NaNs at
the place where there would have been complex). This may create problems for
some MOD files; the algorithms will need to be adapted to use a more
line-search method.

Do not use varargin.

Database was not updated with auxiliary variables.

See b7e6ac58

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It actually does not prevent crashes, see for example:
https://git.dynare.org/Dynare/dynare/-/jobs/4314

This reverts commit 3cf650a2.

— Ondra Kamenik has agreed to the relicensing of utils and parser modules to
  GPL
— add DynareTeam’s copyright, since we have made a lot of modifications
— add proper copyright notices in all files

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Ref #1644

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