libcanlock is a standalone implementation of RFC 8315 Netnews Cancel-Locks
without external dependencies.  It uses the recommended algorithm from
Section 4 of the RFC with HMAC based on the same hash function as the
selected Cancel-Lock scheme.

The package installs:
- libcanlock, a C library for creating and verifying Cancel-Locks;
- canlock, a command line frontend to the library;
- libcanlock-hp and the canlock-hfp/canlock-mhp utilities, which parse
  Cancel-Lock and Cancel-Key article header fields (RFC 8315 receivers).