[HAL] Exclude HAL source files from default build

CMakeLists.txt

@@ -26,6 +26,10 @@ file(GLOB_RECURSE RADIOLIB_SOURCES
   "src/*.cpp"
 )
 
+# exclude all HAL source files, except the default Arduino HAL
+list(FILTER RADIOLIB_SOURCES EXCLUDE REGEX "src/hal/.*\\.cpp")
+list(APPEND RADIOLIB_SOURCES "src/hal/Arduino/ArduinoHal.cpp")
+
 add_library(RadioLib ${RADIOLIB_SOURCES})
 
 target_include_directories(RadioLib

examples/NonArduino/Pico/CMakeLists.txt

@@ -20,6 +20,7 @@ add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/../../../../RadioLib" "${CMAKE_CUR
 
 add_executable(${PROJECT_NAME}
     main.cpp
+    "${CMAKE_CURRENT_SOURCE_DIR}/../../../../RadioLib/src/hal/RPiPico/PicoHal.cpp"
 )
 
 # Pull in common dependencies