message: Fix definitions of constants for RngSupport
  At a low-enough optimization level, even integral constants can end up
  odr-used; that causes a link-time failure, if they don't have a definition.
diff: @@ -40,10 +40,8 @@ bool RngSupport::CheckSeed(const uint8 *seed, uint64 seed_bytes) {
  return true;
  }
  -#if defined(__APPLE__) || defined(__FreeBSD__)
  const int RngSupport::kMinSeedBytes;
  const int RngSupport::kMaxSeedBytes;
  -#endif
  } // namespace rng
  } // namespace stream_executor
  