Add scripts to check the status of nix_builder.

nix/configuration/roles/hydra/default.nix

@@ -10,6 +10,19 @@
   ...
 }:
 
+let
+  patchScriptBin =
+    filename: contents:
+    ((pkgs.writeScriptBin filename contents).overrideAttrs (old: {
+      buildCommand = "${old.buildCommand}\n patchShebangs $out";
+    }));
+  cache_status_full = (
+    patchScriptBin "cache_status_full" (builtins.readFile ./files/cache_status_full.bash)
+  );
+  cache_status_latest = (
+    patchScriptBin "cache_status_latest" (builtins.readFile ./files/cache_status_latest.bash)
+  );
+in
 {
   imports = [ ];
 
@@ -26,6 +39,8 @@
     environment.systemPackages = with pkgs; [
       nix_builder.packages.x86_64-linux.default
       sqlite # For manually inspecting the database.
+      cache_status_full
+      cache_status_latest
     ];
 
     environment.persistence."/persist" = lib.mkIf (config.me.mountPersistence) {