lomiri.lomiri: Try to consider services.xserver.xkb.layout

Propagate the configuration setting through an envvar, check the envvar in the compositor.
Needed because querying AccountsSettings for this information fails, due to Ubuntu-only
"InputSources" interface. So you're stuck on US layout without this hack.

(cherry picked from commit 2735184f6d)

nixos/modules/services/desktop-managers/lomiri.nix

@@ -37,6 +37,10 @@ in {
         suru-icon-theme
         # telephony-service # currently broken: https://github.com/NixOS/nixpkgs/pull/314043
       ]);
+      variables = {
+        # To override the keyboard layouts in Lomiri
+        NIXOS_XKB_LAYOUTS = config.services.xserver.xkb.layout;
+      };
     };
 
     hardware.pulseaudio.enable = lib.mkDefault true;

pkgs/desktops/lomiri/applications/lomiri/9902-lomiri-Check-NIXOS_XKB_LAYOUTS.patch

@@ -0,0 +1,29 @@
+From 640cab41986fac83742af39dd19877041a2ab8dc Mon Sep 17 00:00:00 2001
+From: OPNA2608 <opna2608@protonmail.com>
+Date: Sat, 1 Jun 2024 00:22:27 +0200
+Subject: [PATCH] Check NIXOS_XKB_LAYOUTS for layouts before falling back to
+ "us"
+
+---
+ plugins/AccountsService/AccountsService.cpp | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/plugins/AccountsService/AccountsService.cpp b/plugins/AccountsService/AccountsService.cpp
+index bcf18246c..f4a7dfaa1 100644
+--- a/plugins/AccountsService/AccountsService.cpp
++++ b/plugins/AccountsService/AccountsService.cpp
+@@ -295,6 +295,11 @@ QStringList AccountsService::keymaps() const
+         return simplifiedMaps;
+     }
+ 
++    char* fallbackNixosLayouts = getenv("NIXOS_XKB_LAYOUTS");
++    if (fallbackNixosLayouts != NULL && fallbackNixosLayouts[0] != '\0') {
++        return QString(fallbackNixosLayouts).split(QLatin1Char(','), Qt::SkipEmptyParts);
++    }
++
+     return {QStringLiteral("us")};
+ }
+ 
+-- 
+2.42.0
+

pkgs/desktops/lomiri/applications/lomiri/default.nix

@@ -117,6 +117,7 @@ stdenv.mkDerivation (finalAttrs: {
     })
 
     ./9901-lomiri-Disable-Wizard.patch
+    ./9902-lomiri-Check-NIXOS_XKB_LAYOUTS.patch
   ];
 
   postPatch = ''