Move cross configuration into new file

configuration.nix

@@ -54,33 +54,4 @@
 
   networking.wireless.enable = true;
 
-  ### Cross-compilation stuff ###
-  # Natively compiling on the pinecube is infeasible
-
-  nixpkgs.crossSystem = lib.recursiveUpdate lib.systems.examples.armv7l-hf-multiplatform {
-    platform = {
-      name = "pinecube";
-      kernelBaseConfig = "sunxi_defconfig";
-    };
-  };
-
-
-  nixpkgs.overlays = [ (self: super: {
-    # Dependency minimization for cross-compiling
-    cairo = super.cairo.override { glSupport = false; };
-    libass = super.libass.override { encaSupport = false; };
-    gnutls = super.gnutls.override { guileBindings = false; };
-    polkit = super.polkit.override { withIntrospection = false; };
-  }) ];
-
-  # disable more stuff to minimize cross-compilation
-  # some from: https://github.com/illegalprime/nixos-on-arm/blob/master/images/mini/default.nix
-  environment.noXlibs = true;
-  documentation.info.enable = false;
-  documentation.man.enable = false;
-  programs.command-not-found.enable = false;
-  security.polkit.enable = false;
-  security.audit.enable = false;
-  services.udisks2.enable = false;
-  boot.enableContainers = false;
 }

cross-config.nix

@@ -0,0 +1,29 @@
+{ config, lib, pkgs, ... }:
+
+{
+  nixpkgs.crossSystem = lib.recursiveUpdate lib.systems.examples.armv7l-hf-multiplatform {
+    platform = {
+      name = "pinecube";
+      kernelBaseConfig = "sunxi_defconfig";
+    };
+  };
+
+  nixpkgs.overlays = [ (self: super: {
+    # Dependency minimization for cross-compiling
+    cairo = super.cairo.override { glSupport = false; };
+    libass = super.libass.override { encaSupport = false; };
+    gnutls = super.gnutls.override { guileBindings = false; };
+    polkit = super.polkit.override { withIntrospection = false; };
+  }) ];
+
+  # disable more stuff to minimize cross-compilation
+  # some from: https://github.com/illegalprime/nixos-on-arm/blob/master/images/mini/default.nix
+  environment.noXlibs = true;
+  documentation.info.enable = false;
+  documentation.man.enable = false;
+  programs.command-not-found.enable = false;
+  security.polkit.enable = false;
+  security.audit.enable = false;
+  services.udisks2.enable = false;
+  boot.enableContainers = false;
+}

sd-image.nix

@@ -7,6 +7,7 @@ in
   imports = [ 
     <nixpkgs/nixos/modules/installer/cd-dvd/sd-image.nix>
     ./configuration.nix
+    ./cross-config.nix
   ];
 
   sdImage.populateFirmwareCommands = "";