Alignment of stack traces

[Andrew Haley]

Boehm, Hans writes:
 > My patch was actually trying to deal with the fact that pointers and jlongs
 > may not be the same size.  But yours is simpler, and I prefer it.  Here's a
 > slightly revised version that fixes a problem with a forward reference to p.
 > It built and passed a superficial test on Linux/X86.
 > 
 > I would vote for putting it in both branches now, and reverting it in the
 > development tree if we decide to do something more substantial.

That sounds sensible.  I'll do that.

Andrew.