build MCTP zephyr library only when CONFIG_MCTP is enabled

Zephyr does not allow library with no source, which this commit fixes by
guarding the entire CMake file behind CONFIG_MCTP.

Signed-off-by: Benjamin Cabé <[email protected]>

Author: kartben

zephyr/CMakeLists.txt

@@ -1,22 +1,24 @@
 # Copyright (c) 2024 Intel Corporation.
+# Copyright (c) 2025 The Linux Foundation.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
-set(MCTP_SRC ${CMAKE_CURRENT_SOURCE_DIR}/..)
+if(CONFIG_MCTP)
+  set(MCTP_SRC ${CMAKE_CURRENT_SOURCE_DIR}/..)
 
-zephyr_interface_library_named(mctp)
-target_link_libraries(zephyr_interface INTERFACE mctp)
-target_include_directories(mctp INTERFACE ${MCTP_SRC})
+  zephyr_interface_library_named(mctp)
+  target_link_libraries(zephyr_interface INTERFACE mctp)
+  target_include_directories(mctp INTERFACE ${MCTP_SRC})
 
-zephyr_library_named(modules_mctp)
-zephyr_library_link_libraries(mctp)
+  zephyr_library_named(modules_mctp)
+  zephyr_library_link_libraries(mctp)
 
-zephyr_library_sources_ifdef(
-	CONFIG_MCTP
-	${MCTP_SRC}/alloc.c
-	${MCTP_SRC}/crc32.c
-	${MCTP_SRC}/core.c
-	${MCTP_SRC}/log.c
-	${MCTP_SRC}/libmctp.h
-	${MCTP_SRC}/crc-16-ccitt.c
-)
+  zephyr_library_sources(
+    ${MCTP_SRC}/alloc.c
+    ${MCTP_SRC}/crc32.c
+    ${MCTP_SRC}/core.c
+    ${MCTP_SRC}/log.c
+    ${MCTP_SRC}/libmctp.h
+    ${MCTP_SRC}/crc-16-ccitt.c
+  )
+endif()