message: Fix iOS build failure
  Removed absl::StrCat() usage.
diff: @@ -57,8 +57,7 @@ std::string GetElementwiseWithTwoInputsCode(int src_count,
  if (scalar == nullptr) {
  code += " FLT4 src_1 = src_buffer1[linear_index];";
  } else {
  - code +=
  - absl::StrCat(" FLT4 src_1 = FLT4(", std::to_string(*scalar), ");");
  + code += " FLT4 src_1 = FLT4(" + std::to_string(*scalar) + ");";
  }
  switch (op_type) {
  case OperationType::DIV: {
  