darwin compatibility logic & darwin mcp

modules/dev/emacs/common.nix

@@ -5,28 +5,47 @@
   emacsExtraConfig,
   emacsExtraPackages,
 }:
+let
+  clipboardPackages =
+    if pkgs.stdenv.isDarwin then
+      builtins.attrValues {
+        inherit (pkgs) pngpaste;
+      }
+    else
+      builtins.attrValues {
+        inherit (pkgs)
+          xclip
+          wl-clipboard-rs
+          ;
+      };
+  linuxWindowPackages = lib.optionals pkgs.stdenv.isLinux (
+    builtins.attrValues {
+      inherit (pkgs.xorg) xwininfo;
+      inherit (pkgs) xdotool;
+    }
+  );
+in
 {
-  packages = builtins.attrValues {
-    inherit (pkgs.xorg) xwininfo;
-    inherit (pkgs)
-      xdotool
-      xclip
-      wl-clipboard-rs
-      fd
-      fzf
-      ripgrep
-      tree-sitter
-      graphviz
-      tetex
-      languagetool
-      yaml-language-server
-      markdownlint-cli
-      ;
-    inherit (pkgs.nodePackages)
-      vscode-json-languageserver
-      prettier
-      ;
-  };
+  packages =
+    linuxWindowPackages
+    ++ clipboardPackages
+    ++ builtins.attrValues {
+      inherit (pkgs)
+        fd
+        fzf
+        ripgrep
+        tree-sitter
+        graphviz
+        tetex
+        languagetool
+        yaml-language-server
+        markdownlint-cli
+        ;
+      inherit (pkgs.nodePackages)
+        vscode-json-languageserver
+        prettier
+        ;
+    };
   extraPackages =
     epkgs:
     let