🚀 go-pugleaf

Compiling vault.c in NetHack 3.0 patchlevel 3 yields a compiler error:
"schain botch". I'm not particularly interested in ideas on how to
work around this; obviously the simplest answer is to rewrite the
code. (At the moment, our NetHack3 has no vaults at all :-) ) I am,
however, interested to hear if anybody else has ever run into this and
what it might mean. Anyone not interested in the specifics need not
read further...

The hardware: DEC MicroVax II
The OS:       BSD 4.3 UNIX(tm)
              installed by someone else of unknown competence
The context:  A relatively deep set of for and while loops, the
              deepest level of which contains a forward-referenced
              goto. I don't think the goto is the problem. If I
              comment out the goto and keep the destination label, I
              still get the error.
disclaimer:   this is not a particularly pressing problem; I do want
              to avoid it in the future.