Heap overflow checking fails on darwin/x86

[Raymond Toy]

cmulisp -dynamic-space-size 64
* (defvar *1* (make-list 10000000))

; [GC threshold exceeded with 35,359,432 bytes in use.  Commencing GC.]
; [GC completed with 21,504,336 bytes retained and 13,855,096 bytes freed.]
; [GC will next occur when at least 53,504,336 bytes are in use.]
; [GC threshold exceeded with 53,514,472 bytes in use.  Commencing GC.]
*A2 gc_alloc_new_region failed, nbytes=8.
 CMUCL has run out of dynamic heap space (64 MB).
  You can control heap size with the -dynamic-space-size commandline option.
sigbus_handler: Real protection violation at 0xac3, PC = 0x4b3243e3
...

This probably happens in older versions too, but I didn't check. Works ok on linux.

[Raymond Toy]

Not sure what's changed, but this works now on the 2012-08 snapshot.

Closing (worksforme) for now.