def write_omp_flags(openmp_flag="-fopenmp"):
    """Adds flags for OpenMP parallelization"""
    text = f"""ifeq ($(UNAME_S), Darwin)
OMP_CFLAGS = -Xpreprocessor {openmp_flag} -lomp
else
OMP_CFLAGS = {openmp_flag}
endif

"""
    return text