--- a/glib/tests/cxx.cpp        2022-01-06 14:21:52.890000000 +0000
+++ b/glib/tests/cxx.cpp        2022-01-06 14:22:11.180000000 +0000
@@ -56,7 +56,7 @@
 int
 main (int argc, char *argv[])
 {
-  g_test_init (&argc, &argv, NULL);
+  g_test_init (&argc, &argv, nullptr);
 
   g_test_add_func ("/C++/typeof", test_typeof);