libbacktrace and darwin

[Jack Howarth]

   Is libbacktrace currently functional in gcc trunk and is it expected
to function on darwin? While I could understand it not working on installed
binaries of FSF gcc that were stripped, I would think it should work for 
make check in the build tree since all of the debug code should be present
in the object files. Or doesn't libbacktrace know to look there for the
dwarf code? Thanks in advance for any clarifications.
          Jack