crane

To cross compiling a rust program for windows, run the following in a fresh directory:

nix flake init -t github:ipetkov/crane#cross-windows

Alternatively, if you have an existing project already, copy and paste the following flake.nix:

{
  description = "Cross compiling a rust program for windows";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";

    crane.url = "github:ipetkov/crane";

    flake-utils.url = "github:numtide/flake-utils";

    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs =
    {
      nixpkgs,
      crane,
      flake-utils,
      rust-overlay,
      ...
    }:
    flake-utils.lib.eachDefaultSystem (
      system:
      let
        pkgs = import nixpkgs {
          overlays = [ (import rust-overlay) ];
          localSystem = system;
          crossSystem = {
            config = "x86_64-w64-mingw32";
            libc = "msvcrt";
          };
        };

        craneLib = (crane.mkLib pkgs).overrideToolchain (
          p:
          p.rust-bin.stable.latest.default.override {
            targets = [ "x86_64-pc-windows-gnu" ];
          }
        );

        my-crate = craneLib.buildPackage {
          src = craneLib.cleanCargoSource ./.;

          strictDeps = true;
        };
      in
      {
        packages = {
          inherit my-crate;
          default = my-crate;
        };

        checks = {
          inherit my-crate;
        };
      }
    );
}