CMake: Move netsocket stubs to the netsocket dir

Move the connectivity netsocket stubs into the connectivity/netsocket
component directory. So we can avoid duplicating the mbed-os source
tree in a central UNITTESTS folder.

UNITTESTS/stubs/connectivity/CMakeLists.txt

@@ -19,17 +19,9 @@ target_compile_definitions(mbed-stubs-connectivity
 target_sources(mbed-stubs-connectivity
     PRIVATE
         aes_stub.c
-        CellularInterface_stub.cpp
         cipher_stub.c
         cmac_stub.c
         ip4tos_stub.c
-        MeshInterface_stub.cpp
-        NetworkInterfaceDefaults_stub.cpp
-        NetworkInterface_stub.cpp
-        NetworkStack_stub.cpp
-        nsapi_dns_stub.cpp
-        SocketAddress_stub.cpp
-        SocketStats_Stub.cpp
         stoip4_stub.c
         ${mbed-os_SOURCE_DIR}/connectivity/nanostack/coap-service/test/coap-service/unittest/stub/mbedtls_stub.c
 )

connectivity/netsocket/tests/UNITTESTS/CMakeLists.txt

@@ -1,4 +1,5 @@
 # Copyright (c) 2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
+add_subdirectory(doubles)
 add_subdirectory(netsocket)

connectivity/netsocket/tests/UNITTESTS/doubles/CMakeLists.txt

@@ -0,0 +1,25 @@
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+add_library(mbed-stubs-netsocket)
+
+target_sources(mbed-stubs-netsocket
+    PRIVATE
+        CellularInterface_stub.cpp
+        MeshInterface_stub.cpp
+        NetworkInterfaceDefaults_stub.cpp
+        NetworkInterface_stub.cpp
+        NetworkStack_stub.cpp
+        nsapi_dns_stub.cpp
+        SocketAddress_stub.cpp
+        SocketStats_Stub.cpp
+)
+
+target_link_libraries(mbed-stubs-netsocket
+    PRIVATE
+        mbed-stubs-rtos-headers
+        mbed-headers
+        mbed-stubs-headers
+        mbed-stubs-rtos
+        gtest
+)