clevis-decrypt-tang in fennel

needs a lot of tidying up, but works on my test file

pkgs/tangc/default.nix

@@ -0,0 +1,41 @@
+{
+  fetchurl,
+  writeFennel,
+  fennel,
+  fennelrepl,
+  runCommand,
+  jose,
+  lua,
+  anoia,
+  lualinux,
+  fetch-freebsd,
+  openssl,
+  rxi-json,
+  makeWrapper,
+  stdenv
+}:
+let name = "tangc";
+in stdenv.mkDerivation {
+  inherit name;
+  src = ./.;
+
+  buildInputs = [fetch-freebsd rxi-json openssl lua jose];
+  nativeBuildInputs = [ makeWrapper ];
+
+  buildPhase = "";
+  installPhase = ''
+    mkdir -p $out/bin
+    cp -p ${writeFennel name {
+      packages = [
+        fetch-freebsd
+        rxi-json
+        fennel
+        anoia
+        lualinux
+        jose
+      ] ;
+      mainFunction = "run";
+    } ./tangc.fnl } $out/bin/${name}
+    wrapProgram $out/bin/${name} --set JOSE_BIN ${jose}/bin/jose
+  '';
+}