`PRIMA_INTEGER_KIND = 16` affects solvers' behavior if compiled with `gfortran -Ofast -fno-stack-arrays`

[zaikunzhang]

If we set PRIMA_INTEGER_KIND to 16, meaning to use 16-bit integers for internal calculations, then the following solvers behave visibly differently from the standard version when the Fortran code is compiled by gfortran -Ofast -fno-stack-arrays.

UOBYQA, 1--100-dimensional problems NEWUOA, 1--200-dimensional problems BOBYQA, 1--200-dimensional bound-constrained problems

The same difference is not observable on other solvers or when the code is compiled with gfortran -ffast-math.

This is unexpected.

See the artifacts of https://github.com/primalib/prima/actions/workflows/profile_int16.yml for the results.