* The macOS snapshot until this point did not work unless the user had already installed `libmatio`, `gsl`, and `gcc` via Homebrew.
* We are not modifying `m4/ax_matio.m4` as we want to still be able to compile against shared libraries in development
- Use the -static flag when linking Dynare++, so that shipping libquadmath and
libgcc DLL in the installer is no longer needed.
- Use AM_CXXFLAGS and AM_LDFLAGS variables for changing flags, since CXXFLAGS
and LDFLAGS are user variables. Also, this avoids passing these flags down to
configure scripts in subdirectories.
- Check for the SZIP library in the configure test for the MatIO, this is
needed under MSYS2.
- Statically link MatIO and GSL in MEX files for MATLAB, this is needed under
MSYS2.