Add deprecation warning for those who enable LWIP or NANOSTACK

This is dropped by linker so does not cause any RAM/ROM cost.

features/deprecated_warnings/FEATURE_LWIP/feature_lwip_is_deprecated.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "platform/mbed_toolchain.h"
+
+
+MBED_DEPRECATED_SINCE("5.10", "FEATURE_LWIP is deprecated. You do not need to enable it anymore in mbed_app.json")
+static void feature_lwip(void) { }
+void dummy_feature_lwip_is_deprecated(void) { feature_lwip(); }

features/deprecated_warnings/FEATURE_NANOSTACK/feature_nanostack_is_deprecated.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "platform/mbed_toolchain.h"
+
+
+MBED_DEPRECATED_SINCE("5.10", "FEATURE_NANOSTACK is deprecated. You do not need to enable it anymore in mbed_app.json")
+static void feature_nanostack(void) { }
+void dummy_feature_nanostack_is_deprecated(void) { feature_nanostack(); }