Function _nfloat_add_4 

pub unsafe extern "C" fn _nfloat_add_4(
    res: nfloat_ptr,
    x: nn_srcptr,
    xexp: slong,
    xsgnbit: c_int,
    y: nn_srcptr,
    delta: slong,
    ctx: *mut gr_ctx_struct,
) -> c_int