How do I install packages with machine builds?

[halfer]

Ah, I bet that this the same as this:

Cannot install PHP 7.1 on `machine` because of locked /var/lib/dpkg/lock file

Aha! A quick bit of duck-duck-going lead to this solution for someone having the same problem. Looks like it is a problem with Systemd generally. I don’t think I have seen this reported here before. I wonder whether people would normally install things like PHP first, and then do their checkout. You have them reversed, which perhaps gave the machine more time to throw a spanner in the works.