Thanks for all the help. Unfortunately, it turned out to be a problem with
gcc refusing to build wrapper the right way.
I 3-stage-compiled 2.7.1 for Solaris, built Perl 5.000 (downgraded from
5.001) and re-did the whole thing, from scratch and exactly like the
destructions said. It built and worked. For giggles, I went back and tried
to build it again (in a different directory) using the old gccs I had laying
around (2.6.0 and 2.7.1 single-stage compiled). It failed. Since everything
was identical otherwise, it seems clear to me that I was dealing with a fluke
compiler oddity (or Perl 5.001m hates gcc)
Thanks again for the sanity checks and help.