message: Fix breakages in OSS builds when tstring is enabled.
diff: @@ -16,6 +16,7 @@ limitations under the License.
  #ifndef TENSORFLOW_CORE_PLATFORM_TSTRING_H_
  #define TENSORFLOW_CORE_PLATFORM_TSTRING_H_
  +#include <ostream>
  #include <string>
  // TODO(b/138799229): Used to toggle until global presubmits pass.
  @@ -160,12 +161,14 @@ class tstring {
  return T(str_.data(), str_.size());
  }
  +#ifdef PLATFORM_GOOGLE
  template <typename T,
  typename std::enable_if<std::is_same<T, absl::AlphaNum>::value,
  T>::type* = nullptr>
  operator T() const {
  return T(str_);
  }
  +#endif // PLATFORM_GOOGLE
  bool empty() const { return str_.empty(); }
  