new version of PCL - 1/26/87

[Gregor.pa@Xerox.COM]

There is a new version of PCL on parcvax.xerox.com.  The
*pcl-system-date* is "1/26/87".  This version works in Genera (Symbolics
7.0), Lucid, and Franz (ExCL 1.5) Common Lisps.  I have not tested it
personally in other implementations.

It includes:
 - the ExCL environment patch
 - a work-around for the previous Lucid compiler bug.
 - a fix of the infamous slot values don't override bug, this fix was
done
   by re-writing the code involved to use a modularity which separates
   ordering slots from merging their descriptions.  Please use this
version
   rather than the fix mailed out by Ricks which causes a different bug
   to crop up.