Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC: r260041

Record the IEEE P1282 Rock Ridge version 1.12 POSIX File Serial Number,
i. e. the POSIX:5.6.1 st_ino field, which can be used to detect hard links
in the file system. This is also the default in mkisofs(8) and according to
its man page, no system only being able to cope with Rock Ridge version 1.10
is known to exist.

PR: 185138
Submitted by: Kurt Lidl

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Sync with the latest version from NetBSD. It notably addds ISO9660 support.

Submitted by: bapt