modules/performance: add an option to combine plugins to a single plugin pack

modules/performance.nix

@@ -0,0 +1,54 @@
+{ lib, ... }:
+let
+  inherit (lib) types;
+in
+{
+  options.performance = {
+    combinePlugins = {
+      enable = lib.mkEnableOption "combinePlugins" // {
+        description = ''
+          Whether to enable EXPERIMENTAL option to combine all plugins
+          into a single plugin pack. It can significantly reduce startup time,
+          but all your plugins must have unique filenames and doc tags.
+          Any collision will result in a build failure.
+          Only standard neovim runtime directories are linked to the combined plugin.
+          If some of your plugins contain important files outside of standard
+          directories, add these paths to `pathsToLink` option.
+        '';
+      };
+      pathsToLink = lib.mkOption {
+        type = with types; listOf str;
+        default = [ ];
+        example = [ "/data" ];
+        description = "List of paths to link into a combined plugin pack.";
+      };
+    };
+  };
+
+  config.performance = {
+    # Set option value with default priority so that values are appended by default
+    combinePlugins.pathsToLink = [
+      # :h rtp
+      "/autoload"
+      "/colors"
+      "/compiler"
+      "/doc"
+      "/ftplugin"
+      "/indent"
+      "/keymap"
+      "/lang"
+      "/lua"
+      "/pack"
+      "/parser"
+      "/plugin"
+      "/queries"
+      "/rplugin"
+      "/spell"
+      "/syntax"
+      "/tutor"
+      "/after"
+      # ftdetect
+      "/ftdetect"
+    ];
+  };
+}