Xenix sys/select.h for System V?

[John Temples]

I'm trying to port TinyMUD to System V/386.  This program was originally
written on a BSD system and then ported to Xenix.  Then Xenix version
uses FIFOs in place of the BSD sockets.  Everything seems to compile
fine under System V, except I don't have sys/select.h and a group of
macros I assume are in it: FD_SETSIZE, FD_ISSET, FD_SET, FD_CLR, and
FD_ZERO.  There's also a missing typedef for "fd_set".  Has anyone
already ported this program to System V, or can you point me to a
System V equivalent for these Xenix functions?
-- 
John W. Temples -- john at jwt.UUCP (uunet!jwt!john)