* print.c (scm_iprin1): Rather than having one i, and using it in

* print.c (scm_iprin1): Rather than having one i, and using it in
several places, declare a fresh i local to each block where it is
used, and give it a signedness appropriate to its use in each case.
(scm_iprlist): Same.
* print.c (scm_iprin1): Add cast to avoid unsigned/signed
comparison warnings.
* print.c (ENTER_NESTED_DATA): Make i an unsigned long, to avoid
signed/unsigned clashes.