fix bug when setting up the jmp_buf for exception handling.
fix bug when setting up the jmp_buf for exception handling.

Ignore-this: da6035828ccc0322b7aafee610935e4c

darcs-hash:20100719063036-1a7c6-09575a25ba05ef60690d1988840a71b5bcc6162e

kirbyfan64/jhc,kirbyfan64/jhc,kirbyfan64/jhc,kirbyfan64/jhc