MFC r277610 (by jillies):

Add futimens and utimensat system calls.

Merge r263232 from head to stable/10:

Rename capability.h to capsicum.h: the original name conflicts with the
draft POSIX.1e capability.h used on some systems (e.g., Linux). On
FreeBSD, leave a wrapper header so that current code continues to compile.

We will eventually want to deprecate the old header as the presence of a
capability.h may be confusing some configure scripts.

Suggested by: David Drysdale <drysdale at google.com>
Discussed on: cl-capsicum-discuss
MFC after: 3 weeks

Sponsored by: Google, Inc.

Merge r263232 from head to stable/10:

Rename capability.h to capsicum.h: the original name conflicts with the
draft POSIX.1e capability.h used on some systems (e.g., Linux). On
FreeBSD, leave a wrapper header so that current code continues to compile.

We will eventually want to deprecate the old header as the presence of a
capability.h may be confusing some configure scripts.

Suggested by: David Drysdale <drysdale at google.com>
Discussed on: cl-capsicum-discuss
MFC after: 3 weeks

Sponsored by: Google, Inc.