libstdc++ configury fix for darwin exports

[Geoffrey Keating <geoffk at apple dot com>]

When trying to work out which versioning scheme to use, libstdc++  
looks for a shared libgcc and disables versioning if there isn't  
one.  This isn't a good idea on Darwin, because (a) it uses '-lgcc_s'  
to look for it and it's not called that on Darwin, and (b) on Darwin,  
the "versioning" works just fine even if you link with the static  
libgcc (although this is a very bad idea for other reasons).

So, patch!

Bootstrapped on powerpc-darwin8, and tested by noting that the  
versioning is now 'darwin-export'.

Attachment: gcc-darwin-minversion-libstdc++configury.patch
Description: Binary data

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