Using m2-* build environment on Windows

### Your question:

I've done a little work trying to leverage the current GCC toolchain to build the emacs feedstock directly on Windows using the current msys2 environments to run the build process. The current state is summarized in

- https://github.com/conda-forge/emacs-feedstock/issues/54#issuecomment-2592679753

I think the sed script and bld.bat I've written is probably generic enough to work with any package that has a working build.sh and an MSYS2 mingw64 environment package that uses a bash-based build process that can be integrated into build.sh.

However, I have no idea where such auxillary tools should go. I doubt having every source package include its own copies is the right thing.

Any suggestions?