Fix backup module symlinks

modules/microvm.nix

@@ -68,6 +68,10 @@ in
   config = {
     c3d2.deployment.mounts = [ "etc" "home" "var" ];
 
+    # make mounts like /etc /home /var available early so that they can be used in system.activationScripts
+    fileSystems = lib.genAttrs (map (x: "/" + x) config.c3d2.deployment.mounts)
+      (_: { neededForBoot = true; });
+
     microvm = {
       hypervisor = lib.mkDefault "cloud-hypervisor";
       mem = lib.mkDefault 512;