Make sure we can use nix cache for non-cross-compiling

flake.lock

@@ -1,25 +1,6 @@
 {
   "nodes": {
-    "root": {
+    "root": {}
-      "inputs": {
-        "utils": "utils"
-      }
-    },
-    "utils": {
-      "locked": {
-        "lastModified": 1667395993,
-        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    }
   },
   "root": "root",
   "version": 7

flake.nix

@@ -1,10 +1,8 @@
 {
-  inputs.utils.url = "github:numtide/flake-utils";
-
   description = "cryptic-net provides the foundation for an autonomous community cloud infrastructure";
 
   outputs = {
-    self, utils,
+    self,
   }: let
 
     supportedSystems = (import ./nix/pkgs.nix).supportedSystems;

nix/pkgs.nix

@@ -45,9 +45,18 @@ rec {
   default = {
     buildSystem,
     hostSystem ? buildSystem,
-  }: import src {
+  }: import src ({
-    system = buildSystem;
+
-    crossSystem.config = hostSystem;
     inherit overlays;
-  };
+    system = buildSystem;
+
+  } // (if buildSystem == hostSystem then {} else {
+
+    # The nixpkgs cache doesn't have any packages where cross-compiling has been
+    # enabled, even if the target platform is actually the same as the build
+    # platform (and therefore it's not really cross-compiling). So we only set
+    # up the cross-compiling config if the target platform is different.
+    crossSystem.config = hostSystem;
+
+  }));
 }