Meli fails to build on OpenBSD for at least two reasons.
1 - rust-openssl does not yet support LibreSSL 3.2.2 - see
https://github.com/sfackler/rust-openssl/pull/1366 . This would probably
be fixed by building on an earlier version of OpenBSD, like 6.7.
2 (more fundamental) - The create_timer(2) syscall, used in Meli's
PosixTimer, does not exist on OpenBSD.
Possible solutions would be (a) find a timer implementation that works
on OpenBSD, or (b) put all usage of timers behind a feature flag (I'm
not familiar enough with the Meli codebase to know whether this is
feasible).