extract_data_from_object considered dangerous

[Stefan Monnier]

I was just looking at the calling convention of extract_data_from_object
and it seems intrinsically dangerous:

    It returns a char* into a Lisp_Object without associating it with
    any specific Lisp_Object

In some cases, the Lisp_Object into which the result points is freshly
allocated during the call, so once we return from the function, there is
no Lisp_Object reference to it anywhere any more to keep it from
being GC'd.


        Stefan