lib/modules: Test the ability for config to depend on options for compatibility

lib/tests/modules/define-option-dependently.nix

@@ -0,0 +1,16 @@
+{ lib, options, ... }:
+
+# Some modules may be distributed separately and need to adapt to other modules
+# that are distributed and versioned separately.
+{
+
+  # Always defined, but the value depends on the presence of an option.
+  config = {
+    value = if options ? enable then 360 else 7;
+  } 
+  # Only define if possible.
+  // lib.optionalAttrs (options ? enable) {
+    enable = true;
+  };
+
+}