Unable to use MinGW instead of MSVC for building packages on Windows

### Your question:

Hello!

I am trying to contribute the [Lets-Plot](https://github.com/JetBrains/lets-plot) package to conda-forge.
That project is based on Kotlin Native with Python API.

The issue I am facing is that `conda-build` defaults to using MSVC on Windows, but the library needs to be built with MinGW, because Kotlin Native supports only MinGW as a build target for the Windows platform.

Even after configuring `meta.yaml`, `bld.bat`, and `setup.py` to explicitly call MinGW, `conda-build` continues to invoke MSVC.

Steps taken:

- Modified `bld.bat` to configure MinGW.
- Adjusted `setup.py` to link to MinGW binaries.
- Set appropriate environment variables.
- Despite these modifications, `conda-build` continues to use MSVC.

Is there an official way to force `conda-build` to use MinGW for Windows builds? Or are there any known workarounds or future plans to support this?