THRIFT-5225: Use nullptr instead of NULL
Patch: Zezeng Wang

This closes #2168
diff --git a/lib/c_glib/test/testthrifttestclient.cpp b/lib/c_glib/test/testthrifttestclient.cpp
index 20fbcdb..5732996 100644
--- a/lib/c_glib/test/testthrifttestclient.cpp
+++ b/lib/c_glib/test/testthrifttestclient.cpp
@@ -384,11 +384,11 @@
   // create a C client
   tsocket = (ThriftSocket *) g_object_new (THRIFT_TYPE_SOCKET,
                           "hostname", "localhost",
-                          "port", TEST_PORT, NULL);
+                          "port", TEST_PORT, nullptr);
   protocol = (ThriftBinaryProtocol *) g_object_new (THRIFT_TYPE_BINARY_PROTOCOL,
                            "transport",
-                           tsocket, NULL);
-  client = (TTestThriftTestClient *) g_object_new (T_TEST_TYPE_THRIFT_TEST_CLIENT, "input_protocol", protocol, "output_protocol", protocol, NULL);
+                           tsocket, nullptr);
+  client = (TTestThriftTestClient *) g_object_new (T_TEST_TYPE_THRIFT_TEST_CLIENT, "input_protocol", protocol, "output_protocol", protocol, nullptr);
   iface = T_TEST_THRIFT_TEST_IF (client);
 
   // open and send