I am trying to compile tensorflow using clang , 
And getting following error regarding constexpr

```
In file included from /tensorflow/tensorflow/lite/tools/make/downloads/absl/absl/time/clock.h:26:
/tensorflow/tensorflow/lite/tools/make/downloads/absl/absl/time/time.h:1404:55: error: constexpr function's 2nd parameter type 'std::ratio<60>' is not a literal type
constexpr Duration FromInt64(int64_t v, std::ratio<60>) {
                                        ~~~~~~~~~~~~~~^
/toolkit/include/usr/h/public/ratio:100:9: note: 'ratio<60, 1>' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
        struct ratio
               ^

```

This is the relevant piece of code:

```cpp
template <std::intmax_t N>
constexpr Duration FromInt64(int64_t v, std::ratio<1, N>) {
  static_assert(0 < N && N <= 1000 * 1000 * 1000, "Unsupported ratio");
  // Subsecond ratios cannot overflow.
  return MakeNormalizedDuration(
      v / N, v % N * kTicksPerNanosecond * 1000 * 1000 * 1000 / N);
}

constexpr Duration FromInt64(int64_t v, std::ratio<60>) {
  return (v <= (std::numeric_limits<int64_t>::max)() / 60 &&
          v >= (std::numeric_limits<int64_t>::min)() / 60)
             ? MakeDuration(v * 60)
             : v > 0 ? InfiniteDuration() : -InfiniteDuration();
}

```

Thanks if someone can point me to the right direction