spell misbehavior

[utzoo!henry]

Some friends of mine at Rhodnius Inc., running on a System/8000 (a
Z8000 box from Zilog) report that spell(1) has a tendency to go into
infinite loops if one has too many big environment variables.  It is
right against the wall on the 16-bit address space, and that little
extra bit of space consumption blows things up.  On the PDP11 it's
not so crowded, so I have been unable to reproduce this problem on
my 11/44, but it may still be there.  The Rhodnius folks have only
a binary license, so I have no way to find out whether Zilog has
fooled around with the source.