Alternatively, it looks like both gcc and clang export the ia64 c++ exception 
api as <unwind.h>.  (Note that it is called "ia64" as a historical artifact, 
since it was originally developed for ia64).

It looks like it should be easy to have some sj/lj wrappers that use the 
system sj/lj for register saving and jumping, and the <unwind.h> interface to 
destroy intermediate frames.

I'll try to hack up a solution based on this.

Taahir