xdg-desktop-portal-gtk: build without support for notifications

hosts/common/programs/default.nix

@@ -93,6 +93,7 @@
     ./wob
     ./xarchiver.nix
     ./xdg-desktop-portal.nix
+    ./xdg-desktop-portal-gtk.nix
     ./xdg-utils.nix
     ./zeal.nix
     ./zecwallet-lite.nix

hosts/common/programs/xdg-desktop-portal-gtk.nix

@@ -0,0 +1,16 @@
+{ pkgs, ... }:
+{
+  sane.programs.xdg-desktop-portal-gtk = {
+    packageUnwrapped = pkgs.xdg-desktop-portal-gtk.overrideAttrs (upstream: {
+      postPatch = (upstream.postPatch or "") + ''
+        # configure to not advertise the Notification portal.
+        # this can be patched at source level, or after building, at `$out/share/xdg-desktop-portals/portals/gtk.portal`.
+        # by removing this, xdg-desktop-portal won't advertise `org.freedesktop.portal.Notification`,
+        # and so portal-capable applications will prefer the non-portal `org.freedesktop.Notifications`,
+        # which is what most notification daemons (swaync, mako, ...) speak.
+        substituteInPlace data/gtk.portal.in \
+          --replace-fail 'org.freedesktop.impl.portal.Notification;' ""
+      '';
+    });
+  };
+}