Comment 16 for bug 1872175

Ok, it seems after eliminating the above issue the sys_ptrace isn't triggered anymore.
And even if it is it seems not required for the functionality and would be rather unsafe.

Until I get a GPS lock chrony sees:
chronyc> sources
210 Number of sources = 10
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
#? GPS 0 4 3 14 +1115ms[+1115ms] +/- 200ms
#? PPS 0 4 1 14 +2000ms[+2000ms] +/- 69us
^- chilipepper.canonical.com 2 6 17 28 -611us[ -611us] +/- 44ms
...

After a while (and depending on signal quality) it syncs to the PPS.

chronyc> sources
210 Number of sources = 10
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
#x GPS 0 4 177 24 -876ms[ -876ms] +/- 200ms
#- PPS 0 4 177 21 +916us[ +916us] +/- 63us
^- chilipepper.canonical.com 2 6 37 53 +33us[ +33us] +/- 33ms
^- golem.canonical.com 2 6 37 52 +448us[ +448us] +/- 43ms
^- alphyn.canonical.com 2 6 73 50 +552us[ +552us] +/- 110ms
^- pugot.canonical.com 2 6 37 52 -429us[ -429us] +/- 50ms
^- a08.alphasrv.net 2 6 37 53 +1943us[+1943us] +/- 52ms
^- dns02.xstream-labs.com 2 6 37 53 +568us[ +568us] +/- 36ms
^- stratum2-3.NTP.TechFak.U> 2 6 37 53 -861us[ -861us] +/- 14ms
^* mail.masters-of-cloud.de 3 6 37 54 -45us[ -593us] +/- 12ms

Note sometimes it considers the GPS/PPS too noisy, but that might be right as I don't have the most pricey receiver nor the best reception. Or it considers (after a while) the PPS as good, but had already settles on a server and is not combining PPS with it despite the order of magnitude better resolution)
More antennas arriving later this week ...