Sat Sep 18 13:21:46 CEST 2010

const wrapped in bytes

Can we do this without introducing an extra field?  Plan: 

* limit the accesses to b->bufsize to things that actually _allocate_ 
* make that access abstract 
* set bufsize == 0 to mean it's const data, in which case size is the real size

Ok, this seems to work - pending some weird problems associated to the
fact that this is an un-intuitive ugly hack..

I think it also uses a bit too much stack space.

Next problem: longjmp

Nope, that seems to work just fine; just need to make sure you set a
breakpoint at the setjmp.

Same problem as for the JNI port: no decent console output.