Merge pull request #62046 from roberth/pkgs-nixos-expose-all-config

pkgs.nixos: Expose configuration directly

pkgs/top-level/all-packages.nix

@@ -23932,6 +23932,8 @@ in
                 initialRamdisk.
                 The result can be extended in the modules by defining
                 extra attributes in system.build.
+                Alternatively, you may use the result's config and
+                options attributes to query any option.
 
      Example:
 
@@ -23969,10 +23971,13 @@ in
      Note that you will need to have called Nixpkgs with the system
      parameter set to the right value for your deployment target.
   */
-  nixos = configuration:
-    (import (pkgs.path + "/nixos/lib/eval-config.nix") {
-      inherit (pkgs.stdenv.hostPlatform) system;
-      modules = [(
+  nixos =
+    configuration:
+      let
+        c = import (pkgs.path + "/nixos/lib/eval-config.nix") {
+              inherit (pkgs.stdenv.hostPlatform) system;
+              modules =
+                [(
                   { lib, ... }: {
                     config.nixpkgs.pkgs = lib.mkDefault pkgs;
                   }
@@ -23981,7 +23986,9 @@ in
                   then configuration
                   else [configuration]
                 );
-    }).config.system.build;
+            };
+      in
+        c.config.system.build // c;
 
 
   /*