message: Fixed a preprocessor guard in pybind11_absl.h
  tensorflow::StringPiece is an alias to std::string_view only if
  ABSL_USES_STD_STRING_VIEW is defined, otherwise we do need to register
  a type caster for it.
diff: @@ -19,7 +19,7 @@ limitations under the License.
  #include "pybind11/pybind11.h"
  #include "tensorflow/core/platform/stringpiece.h"
  -#if !defined(PYBIND11_CPP17)
  +#ifndef ABSL_USES_STD_STRING_VIEW
  namespace pybind11 {
  namespace detail {
  @@ -36,5 +36,5 @@ struct type_caster<tensorflow::StringPiece>
  } // namespace detail
  } // namespace pybind11
  -#endif // !defined(PYBIND11_CPP17)
  +#endif // ABSL_USES_STD_STRING_VIEW
  #endif // TENSORFLOW_PYTHON_LIB_CORE_PYBIND11_ABSL_H_
  