Releasing the former Stadia file transfer tools

The tools allow efficient and fast synchronization of large directory
trees from a Windows workstation to a Linux target machine.

cdc_rsync* support efficient copy of files by using content-defined
chunking (CDC) to identify chunks within files that can be reused.

asset_stream_manager + cdc_fuse_fs support efficient streaming of a
local directory to a remote virtual file system based on FUSE. It also
employs CDC to identify and reuse unchanged data chunks.

common/errno_mapping.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef COMMON_ERRNO_MAPPING_H_
+#define COMMON_ERRNO_MAPPING_H_
+
+#include "absl/status/status.h"
+#include "absl/strings/string_view.h"
+
+namespace cdc_ft {
+
+// Converts the errno |error_number| to an absl code.
+absl::StatusCode ErrnoToCanonicalCode(int error_number);
+
+// Creates a status by converting the errno |error_number| to an absl code.
+absl::Status ErrnoToCanonicalStatus(int error_number,
+                                    absl::string_view message);
+
+}  // namespace cdc_ft
+
+#endif  // COMMON_ERRNO_MAPPING_H_