This gist shows an overlay that can be applied to the Nix Kismet package to enable cross-compiling with pkgsCross. It also provides a modified Kismet packages with the applied changes.
NOTE: This gist is now obselete, issue was resolved with this PR: NixOS/nixpkgs#276038
QEMU is required to emulate some of the tools in the build environment (pkg-config, protoc, protoc-c). On Debian based systems install with: