Introduce an internal API for dealing with linux sync files,
and use it in the codebase to replace ad-hoc sync file management.
The linux_sync_file_is_valid function is not currently used, but will be
utilized in upcoming commits to implement the
zwp_linux_explicit_synchronization_unstable_v1 protocol.
Changes in v5:
- Meson support.
Changes in v3:
- Use parameter name in function documentation.
- Move kernel UAPI to separate header file.
Changes in v2:
- Add function documentation
- Remove linux_sync_file_wait()
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
