[RFC] Import the rename gnulib module

[Yao Qi]

Pedro Alves <palves@redhat.com> writes:

> The modules this is bringing in likely obsolete some portability
> concerns we had before.  E.g., this brings in realpath/canonicalize_file_name.
> Do we still need gdb_realpath afterwards?
>
> The danger is in gnulib's fallbacks behaving
> different from ours, and for some reason, our fallbacks being what
> we need.
>
> E.g., this this is bringing in readlink; does is behave the same
> as gdbserver's handle_readlink ?  If not, is that a problem?
> Etc.
>
> (If we end up relying on the dependent gnulib modules, we should
> list them s explicit dependencies in gnulib/update-gnulib.sh
> though.)

Yeah, agreed, or we can logically split this patch by importing
dependent modules explicitly first and get rid of gdb code concerning
portability issues.  Then, the patch importing rename module can be
shorter.  I'll give a try.

-- 
Yao (齐尧)