git: 438a1101dc1f..8b83ef067441 - vendor/bc - vendor branch updated

[Stefan Eßer]

The branch vendor/bc has been updated by se:

URL: https://cgit.FreeBSD.org/src/log/?id=438a1101dc1f..8b83ef067441

8b83ef067441 vendor/bc: upgrade to version 6.6.0