The pthread code added to check_disk in 6986aa1 isn't portable and results in timeouts at least on OpenBSD. I asked for advice about it and had a nice detailed reply explaining the situation (https://marc.info/?l=openbsd-tech&m=144421743119272&w=2).
I had a look at fixing it and have something which "works" but isn't correct, but looking at druchoo's comment on the commit on github, I wonder if it works as expected at all anyway? -- Reply to this email on GitHub: https://github.com/monitoring-plugins/monitoring-plugins/issues/1377
