Synchronize game saves.
The following environment variables must be set to run SaveSync.
RETRO_GAMES: The location to which to synchronize the saves. It must be an
existing directory.
RETRO_SAVES: The location from which to synchronize the saves. It must be an
existing directory.
The following environment variables can optionally be set when running SaveSync.
RETRO_BOOTSTRAP: Fully synchronize the source location at startup. Possible values are 1,
true, and yes.