Bug with *print-base* 36

While porting Gilbert Baumann's web browser closure to OpenMCL, I ran
into what looks like a bug in the printer when *print-base* is bound
to 36 and a bignum is printed. The bug is in ccl::%pr-integer, but the
code looked too hairy for me to fix. Below is a transcript that
demonstrates the problem.

Welcome to OpenMCL Version (Beta: Darwin) 0.13.5!
?
? (setq *print-base* 36)
10
? (expt 36 7)
> Error: Array index Z out of bounds for #<SIMPLE-VECTOR 35> .
> While executing: CCL::%PR-INTEGER
> Type :POP to abort.
Type :? for other options.
1 > :pop
? (setq *print-base* 35)
10
? (expt 36 7)
17M10L71
? (1- (expt 35 7))
YYYYYYY
? (ccl::%pr-integer (expt 36 7) 36)
> Error: Array index 35 out of bounds for #<SIMPLE-VECTOR 35> .
> While executing: CCL::%PR-INTEGER
> Type :POP to abort.
Type :? for other options.
1 >