bahaghari/flake: remove all inputs as a design constraint

subprojects/bahaghari/flake.nix

@@ -1,15 +1,44 @@
+# For now, it has
 {
   description = "Specialized set of Nix modules for generating and applying themes.";
 
-  inputs = {
-    flake-utils.url = "github:numtide/flake-utils";
-  };
-
-  outputs = inputs@{ self, ... }:
+  outputs = { ... }:
     let
-      systems = inputs.flake-utils.lib.defaultSystems;
       sources = import ./npins;
-    in inputs.flake-utils.lib.eachSystem systems
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+      ];
+      eachSystem =
+        systems: f:
+        let
+          # Merge together the outputs for all systems.
+          op =
+            attrs: system:
+            let
+              ret = f system;
+              op =
+                attrs: key:
+                attrs
+                // {
+                  ${key} = (attrs.${key} or { }) // {
+                    ${system} = ret.${key};
+                  };
+                };
+            in
+            builtins.foldl' op attrs (builtins.attrNames ret);
+        in
+        builtins.foldl' op { } (
+          systems
+          # add the current system if --impure is used
+          ++ (
+            if builtins ? currentSystem then
+              if builtins.elem builtins.currentSystem systems then [ ] else [ builtins.currentSystem ]
+            else
+              [ ]
+          )
+        );
+    in eachSystem systems
       (system: {
         devShells.default =
           import ./shell.nix { pkgs = import sources.nixos-stable { inherit system; }; };