Twenex SUBFORK, and fix to (STATUS JCL)

[Jon L White <JONL at MIT-MC>]

Your note of
    Date: 16 Aug 1981 1657-EDT
    From:  (Leonard N Zubkoff) <Zubkoff at CMU-20C>
    In-Reply-To: Your message of 15-Aug-81 1534-EDT
is right in that Ryland's suggestion would always "enable" the
characters in the RESCAN buffer -- however, the MacLISP/LEDIT interface
does indeed always read them (the startup and return-from-superior
hooks do an FJ) so that's why we didn't notice any difference between
the two modes.

I've put SUBFORK 50 onto MC and XX which makes the RESCAN subr work the 
way it did before.  I suspect that Chris was "faked out" by a bug
in (STATUS JCL), which I just fixed -- under ITS, the JCL is really
only acquired at startup time, but if the RESCAN subr is to be of
any value for stuffing something to other lisps (as opposed to
stuffing into TECO), then (STATUS JCL) will have to make a try
to retrieve the current scan-line/JCL.  I've patched LISP.EXE.2122
to do this, and edited the sources appropriately.   Note, however,
that doing (STATUS JCL) also resets to null lisp's internal notion 
of what the scan line is; so for two calls in a row, the second is
pretty much guaranteed to get null.