segfault bug

[Matthew Fluet]

> I  ran the code that is segfaulting on a machine here after re-compiling with
> -g (note, -g isn't documented in the man page or in the  html)  and  it  dies
> with
>     gc.c 421: assert(stack->used <= stack->reserved) failed.
> In  the  stack in question, the reserved field is 32768 but the used field is
> 858,927,408.  This is all using the the 2001-10-06 version.
> 
> Is there any way to turn on what used to  be  GC_EVERY_CHECK  in  the  native
> backend?

Currently, no, although it wouldn't be that difficult to add.  (The only
reason it isn't there currently is that GC_EVERY_CHECK goes through the
compiler as a define that is picked up by gcc when compiling the c backend
code.  Really, we want an option that appears as a Control.??? value for
the native backend to inspect.  I could also just scan the define list for
GC_EVERY_CHECK.)  It should be really quick to add in after the holiday.