While we're talking about third party applications and header file
compatibility, does anybody know why SunOS uses O_SYNC as its flag to
tell the kernel to do synchronous writes, while NetBSD, BSD/OS and
probably 4.4BSD use O_FSYNC?

This particular bugaboo is preventing Kerberos 5 from building on
NetBSD/pmax and NetBSD/i386.   I can obviously add hacks to the
configure tree for Kerberos 5 to conditionalize the use of O_SYNC
vs. O_FSYNC, but this will be a good deal more work than simply
changing the header file.

Is O_FSYNC in the POSIX spec or something?

			       _MelloN_