Initial testing suggests that adding libunwind-dev to build-deps resolves this issue.
- Bug#962630: dovecot: FTBFS: test failures on 32-bit ARM Noah Meyerhans
- Bug#962630: Acknowledgement (dovecot: FTBFS: test fail... Noah Meyerhans
- Bug#962630: Acknowledgement (dovecot: FTBFS: test fail... Noah Meyerhans
- Bug#962630: linking with libunwind does not reliably h... Noah Meyerhans
- Bug#962630: proposed fix on salsa Noah Meyerhans
