[commodorejohn]

Thanks to everybody for weighing in, and for all the terrific reference material - it's certainly a rabbit-hole one could get lost going down ;D As I sort of suspected, the answer probably lies in the fact that this particular featureset was in the process of being developed right around the time that the hardware/software I wanted to target was contemporary. Probably what I'll end up doing is just hosting it on my MicroVAX, which is running NetBSD 6 and should have no problems just using the modern POSIX version.