net: config: init: Disable optimization to avoid bounds check warnings

If ipv4_multicast_address[] is not set in the yaml config file,
then compiler may emit this warning which looks like false positive:

net/lib/config/init.c: In function 'ipv4_setup.constprop':
net/lib/config/init.c:599:67: warning: offset '4294967279' outside
                        bounds of constant string [-Warray-bounds]
599 |       ret = parse_mask(ipv4->ipv4_multicast_addresses[j].value,
    |                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~

In file included from zephyr/subsys/net/lib/config/init.c:2028:
build/test/zephyr/include/generated/net_init_config.inc:137:37:
                  note: 'net_init_config_data' declared here
137 | static const struct net_init_config net_init_config_data = {
    |                                     ^~~~~~~~~~~~~~~~~~~~

If user has specified ipv4_multicast_addresses in the yaml file,
there is no warning printed.

Disable optimization to avoid these warnings.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

subsys/net/lib/config/CMakeLists.txt

@@ -6,6 +6,14 @@ zephyr_library_compile_definitions_ifdef(
   )
 
 zephyr_library_sources_ifdef(CONFIG_NET_CONFIG_SETTINGS init.c)
+
+# Disable optimization for only init.c in order to avoid false
+# positives from bounds checking in optimized builds.
+set_source_files_properties(
+  ${CMAKE_CURRENT_SOURCE_DIR}/init.c
+  PROPERTIES COMPILE_OPTIONS "-O0"
+)
+
 zephyr_library_include_directories(${ZEPHYR_BASE}/subsys/net/ip)
 
 if(CONFIG_NET_CONFIG_SETTINGS)