CMake: Move rtos stubs sources to the mbed-os/rtos directory

Move the rtos stub library into the rtos component directory.
so we can avoid duplicating the mbed-os source tree in a central
UNITTESTS folder.

UNITTESTS/stubs/CMakeLists.txt

@@ -123,7 +123,6 @@ add_subdirectory(connectivity)
 add_subdirectory(events)
 add_subdirectory(hal)
 add_subdirectory(platform)
-add_subdirectory(rtos)
 add_subdirectory(storage)
 
 add_library(mbed-stubs INTERFACE)

rtos/CMakeLists.txt

@@ -1,6 +1,10 @@
 # Copyright (c) 2020 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
+if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND BUILD_TESTING)
+    add_subdirectory(tests/UNITTESTS)
+endif()
+
 target_include_directories(mbed-core
     INTERFACE
         .

rtos/tests/.mbedignore

@@ -0,0 +1 @@
+UNITTESTS/*

rtos/tests/UNITTESTS/CMakeLists.txt

@@ -0,0 +1,4 @@
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory(doubles)

rtos/tests/UNITTESTS/doubles/CMakeLists.txt

@@ -3,6 +3,8 @@
 
 add_library(mbed-stubs-rtos)
 
+add_definitions(-DUNITTEST)
+
 target_sources(mbed-stubs-rtos
     PRIVATE
         ConditionVariable_stub.cpp
@@ -17,6 +19,9 @@ target_sources(mbed-stubs-rtos
 
 target_link_libraries(mbed-stubs-rtos
     PRIVATE        
-        mbed-headers
+        mbed-headers-base
-        mbed-stubs-headers
+        mbed-headers-rtos
+        mbed-headers-platform
+        mbed-headers-drivers
+        mbed-headers-hal
 )