Trace with nonstandard Prin1

[MACRAK at MIT-MC (Stavros M. Macrakis)]

I think I mentioned this a long time ago, but here goes again...
It would seem very useful to be able to set the printing function
in a Trace at tracing time, not using whatever Prin1 happens to be
around at print time.  There are two cases:
1. I know how to print something specially (eg a Macsyma expression);
2. non-standad Prin1's used by my system screw up Trace printout.
Both seem like reasonable cases.  Note that you can always define
a function to simulate using runtime Prin1, but not vice versa.
My recollection is that Trace once worked the way I suggest, using
in fact the Trace-time Prin1 as the run-time Prin1.  Tha in itself
is not necessarily the way to do things, but it's a start, as you can
easily enough do ((lambda (prin1) (trace...)) ...).