Merge "Make libbacktrace build with LLVM r275480"

  auto binary_or_err = llvm::object::createBinary(buffer_or_err.get()->getMemBufferRef());

  if (!binary_or_err) {

    BACK_LOGW("failed to create binary for %s in %s: %s", elf_file.c_str(), apk_file.c_str(),

              binary_or_err.getError().message().c_str());

              llvm::toString(binary_or_err.takeError()).c_str());

    return nothing;

  }

  return llvm::object::OwningBinary<llvm::object::Binary>(std::move(binary_or_err.get()),