core: restore core-as-zephyr-module functionality

Author: facchinm

CMakeLists.txt

@@ -1,11 +1,13 @@
 # SPDX-License-Identifier: Apache-2.0
 
+string(REPLACE "__" "_" NORMALIZED_BOARD_TARGET "${NORMALIZED_BOARD_TARGET}")
+
 if (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/variants/${BOARD})
   set(variant_dir variants/${BOARD})
-elseif (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/variants/${BOARD}${NORMALIZED_BOARD_QUALIFIERS})
-  set(variant_dir variants/${BOARD}${NORMALIZED_BOARD_QUALIFIERS})
+elseif (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/variants/${NORMALIZED_BOARD_TARGET})
+  set(variant_dir variants/${NORMALIZED_BOARD_TARGET})
 else()
-  message(FATAL_ERROR "Variant dir not found: variants/${BOARD}, variants/${BOARD}${NORMALIZED_BOARD_QUALIFIERS}")
+  message(FATAL_ERROR "Variant dir not found: variants/${BOARD}, variants/${NORMALIZED_BOARD_TARGET}")
 endif()
 
 if (CONFIG_ARDUINO_API)

cores/arduino/CMakeLists.txt

@@ -7,6 +7,8 @@ if(NOT DEFINED ARDUINO_BUILD_PATH)
 zephyr_sources(zephyrPrint.cpp)
 zephyr_sources(zephyrSerial.cpp)
 zephyr_sources(zephyrCommon.cpp)
+zephyr_sources(USB.cpp)
+zephyr_sources(itoa.cpp)
 
 if(DEFINED CONFIG_ARDUINO_ENTRY)
 zephyr_sources(main.cpp)