gdb stack crawl at point of internal error in WalkerTest

[Jack Howarth <howarth at bromo dot med dot uc dot edu>]

   On darwin, we are seeing an error in Apple's gdb with current gcc trunk..

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42362

This has been closed as invalid in the gcc bugzilla with a recommendation
that the bug be placed on Apple's radar against their gdb. I plan on doing this
but would appreciate any insights on why this particular bug occurs on
older gdb releases with the new VTA code in gcc trunk. Also, is it certain
that this issue can't be addressed with a work-around in gcc trunk? Thanks in
advance for any comments.
            Jack