Fix issue with Python exit codes that masked failures (#56)

Author: Jamie Smith

tools/cmake/mbed-run-greentea-test.in.cmake

@@ -18,6 +18,6 @@ message("Executing: mbedhtrun ${MBEDHTRUN_ARGS_FOR_DISPLAY}")
 
 # Note: For this command, we need to survive mbedhtrun not being on the PATH, so we import the package and call the main function using "python -c"
 execute_process(
-	COMMAND @Python3_EXECUTABLE@ -c "import mbed_host_tests.mbedhtrun; mbed_host_tests.mbedhtrun.main()" ${MBEDHTRUN_ARGS}
+	COMMAND @Python3_EXECUTABLE@ -c "import mbed_host_tests.mbedhtrun; exit(mbed_host_tests.mbedhtrun.main())" ${MBEDHTRUN_ARGS}
 	WORKING_DIRECTORY "@CMAKE_CURRENT_BINARY_DIR@"
 	COMMAND_ERROR_IS_FATAL ANY)

tools/cmake/mbed_generate_configuration.cmake

@@ -91,7 +91,7 @@ if(MBED_NEED_TO_RECONFIGURE)
     file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/mbed_config.cmake)
 
     set(MBEDTOOLS_CONFIGURE_COMMAND ${Python3_EXECUTABLE}
-        -c "import mbed_tools.cli.main\; mbed_tools.cli.main.cli()" # This is used instead of invoking mbed_tools as a script, because it might not be on the user's PATH.
+        -c "import mbed_tools.cli.main\; exit(mbed_tools.cli.main.cli())" # This is used instead of invoking mbed_tools as a script, because it might not be on the user's PATH.
         configure
         -t GCC_ARM # GCC_ARM is currently the only supported toolchain
         -m "${MBED_TARGET}"