purge_addressof bootstrap failure (was fix opt/8634)

[Andreas Tobler]

Janis Johnson wrote:

> I see the same thing on powerpc-unknown-linux-gnu and
> powerpc64-unknown-linux-gnu.

I saw it as well on darwin this morning. A quick look to the regression 
mailing list showed that Zdenek already pushed a solution.
So the regression test from Geoff (this is the one I looked at) showed 
to me that it was not a local problem and I could even profit from the 
analysis already done. Thanks.

Saved me a lot of time. Otherwise I'd have to dig by myself.

Andreas