fixing visibility of port include

CMakeLists.txt

@@ -35,7 +35,7 @@ else()
     )
     target_include_directories(
       ${LIB_FREERTOS_NAME}
-      PRIVATE
+      PUBLIC
       FreeRTOS/FreeRTOS-Kernel/portable/ThirdParty/GCC/Posix/
     )
   else()