PostGreSQL 7.1.3 & SCO OpenServer 5.0.6 problems

I've searched several faqs and news groups, tried using different
./configure options.  Tried tweaking src/Makefile.shlib as discribed in
several usenet posts that I've found on dejanews.com.  I've tried
following the instructions in the SCO specific faq and I can't get past
the following error message:

"fd.c", line 286: error: undefined symbol: NOFILE

I'm wondering if there are any fixes\patches\hacks that work reliably,
since I can't seem to find anything that works, or interpret and
implement what I've read into something that works.  If any one was any
"definitive" instructions, or perhaps can give a more complete
description of what the problem is and what needs to be done to solve
it, perhaps a "to-do list".  Although I haven't looked at the code yet I
did see a couple of people mention that they tweaked fd.c, however I
couldn't find any listings of what the tweaked.

Any help is greatly appreciated, I don't know if anyone has volunteered
their SCO OpenServer 5.0.6 as a guinea pig, but I'm open to that as an
option.

Thank you in advance,
    Levi Senft