Shouldn't this work?

[gwyn at brl-tgr.UUCP]

In currently available C implementations, (void *) data are illegal.
However, (void (*)()) data are legal and quite useful (too bad they
break older versions of PCC).

The proposed use of (void *) in the future C standard is as a generic
pointer, such as malloc(3) should return; one that can be cast into
a pointer to any other datum.  To date this r^ole has been served
by (char *), although that was not the intended use of (char *) and
one desires a separation of these types (for "lint" etc.).