scripts/functions: svn retrieval first tries the mirror for tarballs

The svn download helper looks for the local tarballs dir to see if it
can find a pre-downloaded tarball, and if it does not find it, does
the actual fetch to upstream via svn.

In the process, it does not even try to get a tarball from the local
mirror, which can be useful if the mirror has been pre-populated
manually (or with a previously downloaded tree).

Fake a tarball get with the standard tarball-download helper, but
without specifying any upstream URL, which makes the helper directly
try the LAN mirror.

Of course, if no mirror is specified, no URL wil be available, and
the standard svn retrieval will kick in.

Reported-by: ANDY KENNEDY <ANDY.KENNEDY@adtran.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

# Menu for the native gdbserver

config GDB_GDBSERVER

    bool

    prompt "gdbserver"

    depends on ! BARE_METAL

    help

      Build and install a gdbserver for the target, to run on the target.

if GDB_GDBSERVER

config GDB_GDBSERVER_STATIC

    bool

    prompt "Build a static gdbserver"

    default y

    help

      In case you have trouble with dynamic loading of shared libraries,

      you will find that a static gdbserver comes in handy.

endif # GDB_GDBSERVER

if BARE_METAL

comment "In bare-metal, you'll need to   "

comment "provide your own gdbserver stub."

endif # BARE_METAL