It is fairly easy to replicate. Use stat to examine the timestamps. The test is reliant on the underlying filesystem. I know to avoid builds in my home directory which is typically NFS and prefer a local scratch filesystem which will also be faster. Use df -T . to see the type of filesystem for the current directory.
That's way above my pay grade. I'll take a look tho:
% df -T .
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda3 ext4 287237 98929 168852 37% /aWorking
Installed. No error msg. However 'info zsh' still reports 5.8.apt install texinfo
Interesting!Or you can install and setup command-not-found
Happy to help.For building zsh (or anything) from source, getting all the dependencies installed tends to be easier than digging into Makefiles to skip non-essentials. It'd be really good to get more testing of the current git head. There have been quite a few changes and it'd be good to find any regressions before a release.
Oliver