Because doesn’t OpenBSD block direct syscalls & force everything to go through libc.
How does that work, with syscalls being unable to be called except from the system’s libc? I’d be a bit surprised if any binary’s embedded libc would support this model.
OpenBSD allows system calls being made from shared libraries whose names start with `libc.so.' and all static binaries, as long as they include an `openbsd.syscalls' section listing call sites.