Open:
 o fix new() bug pointed out by "Paul" at inline@perl.org
 o allow assignment to _HASH & _ARRAY (but not _KEYS)
 o change names of _HASH, _ARRAY, and _KEYS (to what?)
 o add a _TIEHASH accessor?
 o allow nesting of structures which aren't _pointers_
 o enum support?
 o #define support?
 o type checking in accessors

Closed:
 o struct typemaps should look up extra info either in magic or hash
 o in the absence of STRUCTS and NOSTRUCTS, any structs will be bound
 o allow anonymous structures
 o overloaded STRUCTS operator: STRUCTS => \d+ means all structs
 o make the default behaviour to bind to all structs