Features:
+* whenever we measure something into a TPM PCR from userspace, write a record in
+ TCG's "Canonical Event Log" format to some file, so that we can reason about
+ how PCR values we manage came to
+ be. https://trustedcomputinggroup.org/resource/canonical-event-log-format/
+
* bootspec: permit graceful "update" from type #2 to type #1. If both a type #1
and a type #2 entry exist under otherwise the exact same name, then use the
type #1 entry, and ignore the type #2 entry. This way, people can "upgrade"