[Bug ada/124143] implement AI12-0331 binding interpretation

[liam at liampwll dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124143

Liam Powell <liam at liampwll dot com> changed:

           What    |Removed                     |Added
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  Attachment #63717|0                           |1
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--- Comment #7 from Liam Powell <liam at liampwll dot com> ---
Created attachment 63718
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=63718&action=edit
untested fix 3

I have just realised that the last fix is still flawed. Attached is what I hope
will be my final revision.