tweak(emacs): use emacs from nixpkgs

So we don't have to rebuild a rolling version of Emacs which is
incredibly unlikely to be cached due to the override.

Author: gekoke

modules/nixos/preferences/default.nix

@@ -0,0 +1,13 @@
+{ lib, ... }:
+let
+  inherit (lib) mkOption;
+  inherit (lib.types) bool;
+in
+{
+  options.elementary.preferences = {
+    allowLongCompilationTimes = mkOption {
+      type = bool;
+      default = false;
+    };
+  };
+}

modules/nixos/programs/emacs/default.nix

@@ -11,7 +11,10 @@ in
   config =
     let
       emacsPackage = pkgs.emacsWithPackagesFromUsePackage {
-        package = pkgs.emacs-pgtk.override { withImageMagick = true; };
+        package =
+          if config.elementary.preferences.allowLongCompilationTimes
+          then pkgs.emacs-unstable-pgtk.override { withImageMagick = true; }
+          else pkgs.emacs29-pgtk;
         config = ./init.el;
         alwaysEnsure = true;
         override = pkgs.callPackage ./overlay.nix { };

modules/nixos/programs/emacs/init.el

@@ -94,6 +94,7 @@
                       tab-mark)))
 
 (use-package indent-bars
+  :ensure nil
   :hook
   (prog-mode . indent-bars-mode)
   (conf-mode . indent-bars-mode)

systems/x86_64-linux/carbon/default.nix

@@ -12,6 +12,10 @@ with lib.elementary;
   ];
 
   elementary = {
+    preferences = {
+      allowLongCompilationTimes = true;
+    };
+
     virtualisation.docker = enabled;
     hardware.nvidia = enabled;
     roles.workstation = enabled;