[Nickle] Bug displaying large imprecise values

[Carl Worth]

I ran into a problem when nickle tries to display very large imprecise
values.

Here's the largest value that works, (when using a 1-bit imprecise):

	> a=imprecise(2**33-1,1);
	> a
	8589934591

And the first value that breaks:

	> a=imprecise(2**33,1);
	> a
	Unhandled exception invalid_unop_value ("ambiguous conversion to int", 17179869183)
	/usr/local/share/nickle/printf.5c:188:     print (f, this_arg, this_fmt, this_base, width, prec, fill);
	    vfprintf (file, "%.-g", ([1]) {})
	/usr/local/share/nickle/command.5c:12:     printf (format, v);
	    display ()
	<stdin>:4:     Command::display (a);

-Carl

-- 
Carl Worth                                        
USC Information Sciences Institute                      cworth at isi.edu