+[8/97 -- from the p.o.v. of the NCG, it is very convenient if
+the offset to the data field is constant and not dependent on
+what scheme of GC being used by the RTS. So much so, that I'm
+uniformly adding a VHS of 1. For schemes using a copying
+collector, that's the forward field. For the one-space collector,
+it's an unused word.
+
+If the change is reverted back to what it was (conditional on
+the setting of _INFO_COPYING), then MachMisc.foHS
+needs to be changed accordingly. -- SOF]
+