ibcs2 on netbsd 4.0.1 vs. 5.1

[Patrick Bennett <pebcomputing+netbsdusers%gmail.com@localhost>]

I am trying to get a legacy application written for SCO OpenServer
5.0.x to run on NetBSD 5.1 under ibcs2 emulation and am having some
trouble.

First, I should point out that I'm doing this using guest virtual
machines under linux kvm on Ubuntu 10.04.

With NetBSD 4.0.1, I had success getting my legacy app to run right
out of the box - my app ran with virtually no modification to the
default installation.  I did not need to install shared libraries,
re-compile the kernel, nada.  The only problems I did encounter with
the application were related to the app's installation paths and
permissions and once I got them correct the app ran well.

On later versions of NetBSD, however, I have not had any success after
many hours of reading docs, googling, tweaking things, etc..  The
application simply sigfaults on execution seemingly no matter what I
try.  On 5.1, amongst other things, I have tried recompiling the
kernel with the COMPAT_IBCS2 option enabled and moving the app's
directory tree under /emul/ibcs2 (this was not necessary on 4.0.1).
Some months ago I tried all this on 5.0.1 and never got it to work
either, though I've forgotten the details now.

I have /not/ tried installing the shared libraries for two reasons: 1)
they were not needed under 4.0.1, and 2) the script
/usr/share/examples/emul/ibcs2/ibcs2-setup, which apparently copies
the shared libraries off of a SCO installation cd, does not exist on
the system as promised by "man compat_ibcs2" (as a matter of fact,
there is not even an "ibcs2" directory on this path!); this script
also does not exist on 4.0.1.

Any one have any tips to get ibcs2 working again for my app as it does
under 4.0.1, or on how to further debug?

Thanks!
Patrick Bennett