Add nix derivation for Freerouting

freerouting/default.nix

@@ -0,0 +1,28 @@
+let
+  # Import nixpkgs to be able to supply reasonable default values for
+  # the anonymous function this file defines.
+  pkgs = import <nixpkgs> {};
+in
+{ stdenv ? pkgs.stdenv
+, fetchurl ? pkgs.fetchurl
+, makeWrapper ? pkgs.makeWrapper
+, jre ? pkgs.jdk17
+}:
+stdenv.mkDerivation rec {
+  name = "freerouting";
+  version = "1.8.0";
+  src = fetchurl {
+      url = "https://github.com/freerouting/freerouting/releases/download/v${version}/${name}-${version}.jar";
+      sha256 = "7b508037cd8111f97655840fdb014ac62f4bcbe0cdd2b244dc87e7d4a7f92c12";
+  };
+  # I fetch the JAR file directly, so no archives to unpack.
+  dontUnpack = true;
+  nativeBuildInputs = [ makeWrapper ];
+  installPhase = ''
+    mkdir -pv $out/share/java $out/bin
+    cp ${src} $out/share/java/${name}-${version}.jar
+  
+    makeWrapper ${jre}/bin/java $out/bin/freerouting \
+      --add-flags "-jar $out/share/java/${name}-${version}.jar"
+    '';
+}