Previously, nodeRestoreTimestamps would do something like
if node.Type == restic.NodeTypeSymlink {
return nodeRestoreSymlinkTimestamps(...)
}
return syscall.UtimesNano(...)
where nodeRestoreSymlinkTimestamps was either a no-op or a
reimplementation of syscall.UtimesNano that handles symlinks, with some
repeated converting between timestamp types. The Linux implementation
was a bit clumsy, requiring three syscalls to set the timestamps.
In this new setup, there is a function utimesNano that has three
implementations:
* on Linux, it's a modified syscall.UtimesNano that uses
AT_SYMLINK_NOFOLLOW and AT_FDCWD so it can handle any type in a single
call;
* on other Unix platforms, it just calls the syscall function after
skipping symlinks;
* on Windows, it's the modified UtimesNano that was previously called
nodeRestoreSymlinkTimestamps, except with different arguments.
