* hashtab.c (scm_vector_to_hash_table,

* hashtab.c (scm_vector_to_hash_table,
scm_c_make_resizing_hash_table, scm_make_hash_table): New
functions.
(scm_hash_fn_get_handle, scm_hash_fn_create_handle_x): Made thread
safe and handle resizing tables.

* weaks.c (scm_make_weak_key_hash_table,
scm_make_weak_value_hash_table, scm_make_doubly_weak_hash_table):
Size argument made optional.  Return resizable table if not
specified.

* boot-9.scm (make-hash-table): Turned primitive.