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>

Signed-off-by: dank@kegel.com

Raising the size of the hash table is a noticable win when linking 

at least one large app.  

There was a patch,

http://sources.redhat.com/ml/binutils/2004-06/msg00165.html

to do this dynamically.  No idea why that didn't make it in.

So this tiny change to raise the default size is just

a stopgap for now.

--- binutils-2.16.1/bfd/hash.c.old	2006-03-02 23:01:39.000000000 -0800

+++ binutils-2.16.1/bfd/hash.c	2006-03-02 23:01:58.000000000 -0800

@@ -300,7 +300,7 @@

 */

 /* The default number of entries to use when creating a hash table.  */

-#define DEFAULT_SIZE 4051

+#define DEFAULT_SIZE 32749

 static size_t bfd_default_hash_table_size = DEFAULT_SIZE;

 /* Create a new hash table, given a number of entries.  */