more debug printing

`p` turned out not to be corrupted on failing systems. Debug print the
contents of `gangcount` and `grandtotal` as they are being updated.
This is for another trial release on the CPAN satellite!
fix incorrect carry call

Fix a bug introduced in 1c83533b where the wrong variable was
carried. Since `grandtotal` is updated, it should be carried, not
`gangcount`.

cherry-picked from master.
New CPAN release of Algorithm-AM - v2.41

    More debug printing
    Fixed big-int bug introduced in 2.40