Ignore lchmod() ENOSYS (i.e. function not implemented)

Ignore lchmod() ENOSYS (i.e. function not implemented)

When restoring symlink permissions, assume that ENOSYS means that it's
not possible to lchmod().

For comparison, it looks like tar doesn't handle lchmod() at all yet.
From the Debian tar 1.27.1 TODO:

  * Add support for restoring the attributes of symbolic links, for
    OSes like FreeBSD that have the lutimes and lchmod functions.

Thanks to Xiao LIU for reporting the problem.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>