I've made a new release to Io_lib (aka staden-io_lib), as a minor bug fix was required for the new main Staden Package release. Practically speaking it likely only impacts MacOS X 10.6 users (I think).
Version 1.12.5 (3rd Feb 2011)
* Fixed detection of requirement for va_copy(); affecting some Mac
* Added hash_exp. I'm not sure this is of pratical use, but it was in
the source tree and in theory at least still works.
* Removed minor memory leak in HashTableResize().