Since I think shell languages make the most sense for calling external programs used for building software, I went through every active entry on the Oil shell project’s (fairly comprehensive!) list of alternative shells to see which of them run on Windows. One in particular stood out (already mentioned here by @symphorien) GSH, a non-interactive POSIX shell for Windows:
GSH is an implementation of a POSIX shell developed for the Windows platform. […]
GSH can be used to compile projects depending on autotools, UNIX make, [etc.] … [GSH] does not depend on the ‘fork system call’ and doesn’t emulate that system call (as it’s done on Cygwin).
It’s not complete yet:
As the project is still not complete you still need a Cygwin installation for the tools not provided by GSH. The only requirement is that the build should be done in a path for which Cygwin path maps directly to a Windows path.
But it still seems quite interesting, since it would be much more similar to the Bash builders we’re using on Unix-like platforms.
Another shell language with native Windows support that stood out as something potentially harmonious with the current Nixpkgs practice of using shell builders was Batsh, a programming language that compiles to GNU Bash and Windows BAT.
Other shell languages from the list that seem easy to build and deploy on Windows (i.e., no special environment like Cygwin or heavyweight language runtime is needed):
Other shell languages that advertise native (non-WSL) Windows support: