API changes breaking CPANs modules with ld errors are not caught by BBC

[ericherman]

Description 0351a629e71de127cbfd1b142e9eaa6069deabf5 hides symbols, some of which were used by CPAN modules.

We noticed that Algorithm-Heapify-XS depends upon Perl_do_ncmp.

And it seems FreeBSD dropped support for other distributions related to this commit:

• Data-Swap
• Devel-BeginLift
• Text-ClearSilver
• Apache-DB

(Note that some had other issues before.)

Steps to Reproduce

If we look at cpantesters, we see the ld failures are "UNKNOWN", and not "FAIL".

To see an example of the kind of failure we'd expect caught, clone demerphq/Algorithm-Heapify-XS and type perl Makefile.PL && make

Expected behavior

Changes made to the API don't break CPAN. It would be expected that BBC would have caught these.