Does not work on Windows without Mingw

[leighmcculloch]

The Rust binary library targets x86_64-pc-windows-gnu which requires mingw on Windows. This causes the Go package to fail to compile if mingw is not installed.

For more seamless support for Windows users the library should also be built to target x86_64-pc-windows-msvc.

Related conversation:

• Add binaries and CI workflow for multi-arch binary verification #7 (comment)