chrony: Update seccomp filter to work with glibc 2.31

[jamieand]

Description of changes:

This is a series of additive patches taken from upstream.

Signed-off-by: Jamie Anderson jamieand@amazon.com

Testing done:

Built an image and verified that chronyd started and found a time source:

# journalctl -x -u chronyd.service
-- Logs begin at Wed 2020-02-26 21:01:17 UTC, end at Wed 2020-02-26 21:02:44 UTC. --
Feb 26 21:01:20 ip-192-168-97-15.us-west-2.compute.internal systemd[1]: Started A versatile implementation of the Network Time Protocol.
-- Subject: A start job for unit chronyd.service has finished successfully
-- Defined-By: systemd
-- Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- A start job for unit chronyd.service has finished successfully.
-- 
-- The job identifier is 58.
Feb 26 21:01:20 ip-192-168-97-15.us-west-2.compute.internal chronyd[2916]: 2020-02-26T21:01:20Z chronyd version 3.5 starting (+CMDMON +NTP +REFCLOCK +RTC +P
RIVDROP +SCFILTER -SIGND +ASYNCDNS -SECHASH +IPV6 -DEBUG)
Feb 26 21:01:20 ip-192-168-97-15.us-west-2.compute.internal chronyd[2916]: 2020-02-26T21:01:20Z Loaded seccomp filter
Feb 26 21:01:26 ip-192-168-97-15.us-west-2.compute.internal chronyd[2916]: 2020-02-26T21:01:25Z Selected source 169.254.169.123

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[jamieand]

Improved readability of spec file comments.