config(nixos): Make sure NixOS config uses same set of overlays as "nix repl"

config/flake/universe/Documentation/default.nix

@@ -53,7 +53,7 @@
       mv ./redoc-static.html $out
     '';
 
-  doc-nixpkgs = import (<snapshot> + "/nixpkgs/doc") {};
+  doc-nixpkgs = import (<nixpkgs> + "/doc") {};
   doc-posix = callPackage ./doc-posix.nix {};
   langzig-reference = fetchurl {
     url = "https://ziglang.org/documentation/0.10.1/index.html";

config/flake/universe/python3/overrides.nix

@@ -41,6 +41,4 @@ self: super: {
       browser-cookie3
     ];
   };
-
-  tkinter = null;
 }

config/nixos/configuration.nix

@@ -54,6 +54,7 @@
 
   fonts.packages = with pkgs; [source-code-pro];
   nixpkgs.config.allowUnfree = true;
+  nixpkgs.overlays = import ../../overlays.nix;
   services.lorri.enable = true;
   services.postgresql = {
     enable = true;

config/nixos/user-kaction.nix

@@ -4,6 +4,7 @@
   home.homeDirectory = "/home/kaction";
   home.packages = [
     pkgs.htop
+    pkgs.Documentation
   ];
 
   programs.emacs = {

default.nix

@@ -1,25 +1,3 @@
-let
-  overlay = self: super: {
-    # Create symlink named "sr-foo" for each surfraw module (elvi).
-    # Unlike "sr foo" they are nicely auto-completed without
-    # programmable completion interface.
-    surfraw = super.surfraw.overrideAttrs (_: {
-      postInstall = ''
-        for elvi in $out/lib/surfraw/* ; do
-          name=$(basename $elvi)
-          ln -sf ../lib/surfraw/$name $out/bin/sr-$name
-        done
-      '';
-    });
-
-    python3 = super.python3.override {
-      packageOverrides = import ./config/flake/universe/python3/overrides.nix;
-    };
-  };
-in
-  import ./nixpkgs {
-    overlays = [
-      overlay
-      (import ./config/flake/default.nix)
-    ];
-  }
+import ./nixpkgs {
+  overlays = import ./overlays.nix;
+}

overlays.nix

@@ -0,0 +1,23 @@
+let
+  overlay = self: super: {
+    # Create symlink named "sr-foo" for each surfraw module (elvi).
+    # Unlike "sr foo" they are nicely auto-completed without
+    # programmable completion interface.
+    surfraw = super.surfraw.overrideAttrs (_: {
+      postInstall = ''
+        for elvi in $out/lib/surfraw/* ; do
+          name=$(basename $elvi)
+          ln -sf ../lib/surfraw/$name $out/bin/sr-$name
+        done
+      '';
+    });
+
+    python3 = super.python3.override {
+      packageOverrides = import ./config/flake/universe/python3/overrides.nix;
+    };
+  };
+in
+[
+    overlay
+    (import ./config/flake/default.nix)
+]