Add unbound config nix package

unbound.nix

@@ -0,0 +1,19 @@
+{
+  stdenvNoCC,
+}:
+stdenvNoCC.mkDerivation {
+  name = "stevenblack-hosts-unbound";
+  src = ./.;
+
+  installPhase =
+    let
+      toUnboundConf = ''awk 'NF == 2 && $1 == "0.0.0.0" && $2 != "0.0.0.0" { printf "local-zone: \"%s\" always_nxdomain\n", $2 }'\'';
+    in
+    ''
+      mkdir $out
+      cat $src/hosts | ${toUnboundConf} > $out/hosts
+      for file in alternates/*/hosts; do
+        cat $file | ${toUnboundConf} > $out/$(basename $(dirname $file))
+      done
+    '';
+}