[Patch, Fortran] PR32987 - Allow TAB in FORMAT statements as extension and warn with -std=f*

[FX Coudert]

:REVIEWMAIL:

> 2007-08-04  Tobias Burnus  <burnus@net-b.de>
>
> 	PR fortran/32987
> 	* io.c (format_token): Add FMT_ERROR.
> 	(next_char_not_space): Print error/warning when
> 	'\t' are used in format specifications.
> 	(format_lex): Propagate error.
> 	(check_format): Ditto.

It looks OK.

> +  c = next_char_not_space (&error);
> +  if (error)
> +    return FMT_ERROR;

We now have to perform a check after each next_char_not_space; this  
seems to me rather heavy (in term of code simplicity/readability) for  
such an extension. Maybe you can think a something that would be less  
heavy (a macro?). Otherwise, it's OK, as I don't really have a good  
suggestion to implement instead :)

FX