base: add option config.virtualisation.vmVariant

base/vm.nix

@@ -0,0 +1,15 @@
+{ lib, ... }:
+
+# This enables
+#     lib.mkIf (!config.virtualisation.isVmVariant) { ... }
+
+{
+  options.virtualisation.isVmVariant = lib.mkOption {
+    description = "`true` if system is build with 'nixos-rebuild build-vm'";
+    type = lib.types.bool;
+    default = false;
+  };
+  config.virtualisation.vmVariant = {
+    virtualisation.isVmVariant = true;
+  };
+}