I am fully aware UNIX clones will never use anything beyond C for most part, although there are some famous UNIXes like Apollo that did indeed trail another path.
The context of this thread is adding syscall to the kernel to allow C userland programs to be safer.
Even if the kernel were written in Java - which is, again, absurd to ask of the OpenBSD developers - it would still be a viable syscall to add for user mode programs written in memory unsafe languages.
I am fully aware UNIX clones will never use anything beyond C for most part, although there are some famous UNIXes like Apollo that did indeed trail another path.