Recent bug fix in XLISP

[Cesar Quiroz]

A few days ago, a fix was posted that can be summarized  as follows:

> A rather serious bug in XLISP causes it to get scrambled if a garbage
> collection occurs at the wrong time.  The following fix, provided by
> the author, cures the problem.
> 
> Try making the following changes to XLEVAL,XLCONT,XLOBJ in every place where
> the variable 'oldnewenv' is mentioned:
> 
> 	/* note that this is a 'NODE' not a 'NODE *' */
> 	NODE ... ,oldnewenv, ...;
> 
> 	.
> 	.
> 	.
> 
> 	oldstk = xlsave( ... ,&oldnewenv, ... ,NULL);
> 
> 	.
> 	.
> 	.
> 
> 	oldnewenv.n_ptr = xlnewenv;
> 
> 	.
> 	.
> 	.
> 
> 	xlnewenv = oldnewenv.n_ptr;
> 

Sorry, but I can't find uses of 'oldnewenv' as a NODE and not a NODE *. 
(Or does it mean 'change all '*oldnewenv' into 'oldnewenv'?)
Can somebody who figured this out please post a diff or something 
we can use to apply the fix?  We have version 1.4, which I assume is
the current one.

Thanks,
Cesar