I was recently looking into something like this. It turns out Fedora is a cross compiling (at least for Windows) powerhouse. It has the compilers but _also_ c

I was recently looking into something like this. It turns out Fedora is a cross compiling (at least for Windows) powerhouse. It has the compilers but _also_ cross-built packages for most standard system libraries (libpng, curl, etc). This is turning into a random info dump, but whatever. Azure Pipelines has free Windows workers in their pool, for open source, with all standard Windows build tools, python, etc. I'm not aware of other CI providers with Windows instances. I wanted to use Guix but wanted to try it out with Docker and there aren't any official packages, ran into a number of issues setting it up manually. Guix has their libraries and build environments abstracted in such a way that it should be possible to build any package with say mingw in a line (or two). Guix also seems to have a stricter versioning system than Nix, where it didn't look trivial to pin specific package/system versions. Gnome msitools has a Wix clone for Windows MSI creation. It's a bit hobbled (doesn't support a lot of fields/parameters).