calculix/CalculiX-Windows — reverse-engineered prompt

Build me a native Windows 64 bit build package for CalculiX, the open source finite element solver for field problems. I want someone on Windows to be able to download the finished release, install it, and run the solver without having to figure out compilers or dependencies.

Please set up the source area so the build script can automatically fetch the CalculiX source code and any needed dependencies if they are not already there, apply the required patches and environment settings, then compile everything into a working Windows release. Keep the project simple, with a src folder for the build scripts and source setup, and a releases folder for ready to install binary packages.

Also include clear basic instructions for building from source and for using the released package. If any Windows build details are tricky, look up the current docs online and make the script as repeatable as possible.