Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Fix pkgfs stat so it satisfies libsecureboot

We need a valid st_dev, st_ino and st_mtime
to correctly track which files have been verified
and to update our notion of time.

ve_utc_set(): ignore utc if it would jump our current time
by more than VE_UTC_MAX_JUMP (20 years).

Allow testing of install command via userboot.
Need to fix its stat implementation too.

bhyveload also needs stat fixed - due to change to userboot.h

Call ve_error_get() from vectx_close() when hash is wrong.

Track the names of files we have hashed into pcr

For the purposes of measured boot, it is important
to be able to reproduce the hash reflected in
loader.ve.pcr
so loader.ve.hashed provides a list of names in the order they
were added.

Reviewed by: imp
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org//D24027

libsecureboot: allow control of when pseudo pcr is updated

During boot we only want to measure things which *must*
be verified - this should provide more deterministic ordering.

Reviewed by: stevek
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D20297

Add libsecureboot

Used by loader and veriexec
Depends on libbearssl

Reviewed by: emaste
Sponsored by: Juniper Networks
Differential Revision: D16335