[gcc 4.5 patch] Permit smaller hash tables for hash_map and hash_set

[Ian Lance Taylor]

> 2009-02-06  Ian Lance Taylor  <iant@google.com>
>
>        * include/backward/hashtable.h (_S_num_primes): Change to 29.
>        (__stl_prime_list): Add 5 at the start of the list.

Now that we are back in stage 1, I have committed this patch.

Ian