Add zephyr/CMakeLists.txt

Created a module-level CMakeLists.txt for extending the include paths
to find "mcuboot-mbedtls-cfg.h" within the boot/zephyr component.

The build of `west build -p always -b nrf52840dk_nrf52840
mcuboot/boot/zephyr` fails with:

CMake Error at /home/zephyr/mcuboot_dev/mcuboot/zephyr/CMakeLists.txt:36 (add_subdirectory):
  add_subdirectory not given a binary directory but the given source
  directory "/home/zephyr/mcuboot_dev/mcuboot/boot/bootutil/zephyr" is not a
  subdirectory of "/home/zephyr/mcuboot_dev/mcuboot/zephyr".  When specifying
  an out-of-tree source a binary directory must be explicitly specified.

The build of `west build -p always -b nrf52840dk_nrf52840
mcuboot/samples/zephyr_external_config` fails with:

CMake Error at /home/zephyr/mcuboot_dev/mcuboot/zephyr/CMakeLists.txt:36 (add_subdirectory):
  add_subdirectory not given a binary directory but the given source
  directory "/home/zephyr/mcuboot_dev/mcuboot/boot/bootutil/zephyr" is not a
  subdirectory of "/home/zephyr/mcuboot_dev/mcuboot/zephyr".  When specifying
  an out-of-tree source a binary directory must be explicitly specified.

Signed-off-by: Gregory SHUE <[email protected]>

Author: legrand-gregshue

zephyr/CMakeLists.txt

@@ -0,0 +1,36 @@
+# Copyright (c) 2022 Legrand North America, LLC.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
+
+
+# Detect the platform reliably
+if(ZEPHYR_BASE)
+else()
+  message(FATAL_ERROR "ZEPHYR_BASE needs to be defined for Zephyr builds")
+endif()
+
+# Verify the module name is set correctly
+set(expected_module_name "mcuboot")
+if(NOT "${module_name}" STREQUAL ${expected_module_name})
+  message(FATAL_ERROR "A module configuration error has occurred.
+This module is named '${module_name}' when '${expected_module_name}' \
+is expected. 
+Verify `module.yml` contains the line 'name: ${expected_module_name}'.")
+endif()
+unset(expected_module_name)
+
+#Do not allow in source builds
+set(CMAKE_DISABLE_SOURCE_CHANGES ON)
+set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
+
+
+#
+# Module options managed through Kconfig and use names CONFIG_*
+#
+
+zephyr_include_directories(../boot/zephyr/include)
+
+add_subdirectory(../boot/bootutil/zephyr)

zephyr/module.yml

@@ -1,5 +1,5 @@
 samples:
   - boot/zephyr
 build:
-  cmake: ./boot/bootutil/zephyr
+  cmake: ./zephyr
   kconfig: ./zephyr/Kconfig