[gfortran] PATCH Fix PR 18537

[Tobias Schlüter]

Steve Kargl wrote:
> The :8: is hardly intuitive.  I tried all of the following
> 
> Warning: At line 8 nonstandard tab character
> Warning: At line 8, nonstandard tab character
> Warning: At line 8: nonstandard tab character
> Warning: In PR18537.f90 at line 8 nonstandard tab character
> Warning: Line 8 nonstandard tab character
> Warning: Line 8: nonstandard tab character

I haven't looked at the precise interaction between the scanner and the locus
machinery in the place you're hacking, but shouldn't the "%C" format work,
i.e. gfc_warning ("Tab character at %C"); (or the corresponding call to emit a
std-warning)?

- Tobi