nix: Make alacritty and other GL apps runnable

Not everyone works, but already something.

config/nix/hm/desktop.nix

@@ -3,7 +3,6 @@
   xsession = {
     enable = true;
     windowManager = {
-      command = "${config.xsession.windowManager.i3.package}/bin/i3";
       i3 = {
         enable = true;
         config =
@@ -439,11 +438,21 @@
   };
 
   home = {
-    file = {
+    file =
+      let
+        nixgl = import
+          (builtins.fetchGit {
+            url = "https://github.com/nix-community/nixGL";
+            rev = "489d6b095ab9d289fe11af0219a9ff00fe87c7c5";
+          })
+          { };
+      in
+      {
         ".xinitrc" = {
+          # TODO Configurable
           source = pkgs.writeShellScript "xinitrc" ''
             ${pkgs.xorg.xrdb}/bin/xrdb ${config.xresources.path}
-          ${config.xsession.windowManager.command}
+            ${nixgl.nixVulkanIntel}/bin/nixVulkanIntel ${nixgl.nixGLIntel}/bin/nixGLIntel ${config.xsession.windowManager.command}
           '';
         };
       };