AIX PATCH: Fix vtable references

[Mark Mitchell]

This patch seems to fix the last of the vtable problems on AIX.

With these changes (and some tweaks to the testsuite to avoid seeing
essentially spurious errors), the AIX `make check-g++' is looking very
good.

David, would you care to apply this patch, and then see what the V3
testsuite looks like these days?  (I'm going to have to work on some
other projects for the rest of the day.)

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Mark Mitchell                   mark@codesourcery.com
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