Sun4os4 /bin/sh dumps core. (was: perl 3.0 dumps core)

[Guy Harris]

>Probably not so.  I have perl 3.0-beta running on Sun 3's (under SunOS 4.0.3)
>but it (or actually sh) dumps core

Uhh, excuse me, but please do NOT assume that because the string "sh:"
appears in the "core dumped" message that it's the shell that's dumping
core.  In fact, in the case I saw when running "make test" on a Sun-4,
it's the shell that's telling you that something *else*, namely Perl,
dumped core - yes, even if your shell is the C shell, since "make" is
running Perl from the Makefile and it uses the Bourne shell for
everything on SunOS. 

If you want to know what program generated a core file on SunOS 3.x or
4.x, do "file core".

The problem is, as Larry Wall and I noted, a "vfork"-related problem
(and merely including <vfork.h> doesn't seem to fix it).