libstdc++, -m64 and can't find atom for N_GSYM stabs

[Eric Christopher]

> Once the noise from those linker warnings is removed from the libstdc++-v3 testsuite
> results at -m64 on Darwin PPC, we find that the failures drop from 54 to just 6. So
> we actually only have four additional libstdc++-v3 testsuite failures at -m64
> compared to -m32. These are...
> 
> FAIL: 21_strings/basic_string/cons/char/1.cc execution test
> FAIL: 21_strings/basic_string/cons/wchar_t/1.cc execution test
> FAIL: 21_strings/basic_string/insert/char/1.cc execution test
> FAIL: 21_strings/basic_string/insert/wchar_t/1.cc execution test
> 
> which certainly would appear as if they are all related bugs. Can you try
> the above check on x86_64 and see how many regressions you have when the
> linker warnings suppressed?

For i386 vs x86_64 I'm getting a different set of pass/fail between the 
two. I do, however, have those 4 failures on x86_64 and not on i386.

-eric