[patch, fortran] Fix for PR 18022

[Tobias Schlüter]

Paul Thomas wrote:
> Regtested under RH9 on an Athlon 1700.  OK to commit to 4.1 and 
> sometime, whenever to 4.0?

No.  I've looked at this in some depth, and your patch works around the real
bug in one special case, but it's easy to generate testcases which fail due to
the underlying bug even in the presence of your patch.  I've added more
detailed information in the audit trail of PR18022.

Thanks,
- Tobi