Test for TARGET_API_MAC_CARBON with #if in stead of #ifdef.
diff --git a/Mac/Modules/Nav.c b/Mac/Modules/Nav.c
index c86a5ef..7a8abc4 100644
--- a/Mac/Modules/Nav.c
+++ b/Mac/Modules/Nav.c
@@ -350,7 +350,7 @@
 				PyErr_Mac(ErrorObject, err);
 				return NULL;
 			}
-#ifdef TARGET_API_MAC_CARBON
+#if TARGET_API_MAC_CARBON
 			if (err=AEGetDescData(&desc, &fss, sizeof(FSSpec))) {
 				Py_DECREF(rv);
 				PyErr_Mac(ErrorObject, err);