Broken write_canonical/2 in B-Prolog 7.5

[Paulo Moura]

The implementation of the standard write_canonical/2 built-in predicate is broken, outputting terms that the standard read_term/3 built-in predicate cannot read back. This bug prevents using B-Prolog 7.5 with Logtalk. The only workaround until the bug is fixed is to revert to the previous B-Prolog version.