I've had sunos emulation set up on one of my sparcs for a long time, and it
used to work well, but it hasn't worked for a while now.  Every time I try to
execute a sunos binary I get:

  ld.so: map heap error (22) for /dev/zero

Now, while I've upgraded NetBSD a few times, I don't think I've changed
anything in the /emul/sunos tree, so I don't think I've broken anything
there.  I'm not sure when it stopped working, but the most recent version
of NetBSD that I've tried this under is 1.3F, built from July 26, 1998
sources.  COMPAT_SUNOS is turned on in the kernel config.  The sunos
executables and libraries are from sunos 4.0.3c or were compiled under
that version of sunos.

So, my questions are:

  * Is sunos emulation still working for other people?

  * Is it possible that compatibility with sunos 4.0.3c is broken, but
    that compatibility with newer versions of sunos still works?

  * Does the error message above give any useful clues about the problem
    (and how to fix it)?

Thanks in advance.