prevent error on specific warnings for net lwip & dual example for rp2040

examples/device/net_lwip_webserver/CMakeLists.txt

@@ -72,6 +72,12 @@ if (EXISTS ${TOP}/lib/lwip/src)
     # Example common such as compiler warnings
     include(${CMAKE_CURRENT_SOURCE_DIR}/../../example.cmake)
 
+    # due to warnings from other net source, we need to prevent error from some of the warnings options
+    target_compile_options(${PROJECT} PUBLIC
+        -Wno-error=null-dereference
+        -Wno-error=conversion
+        )
+
     # Configure compilation flags and libraries for the example... see the corresponding function
     # in hw/bsp/FAMILY/family.cmake for details.
     family_configure_device_example(${PROJECT})