Add software library into system library

You could just copy the source into the system library project. Alternatively, instead of linking against your library using the -l flag, e.g. -lmylib to link against libmylib.a, use the flag -msys-lib, e.g. -msys-lib=mylib. This will allow the linker to resolve the circular dependency problems that I suspect you were having when trying to call library functions from drivers.