[PATCH,gfortran] Remove homegrown isdigit and isalpha in module.c

[Tobias Schlüter]

I forgot to make this explicit...

> Index: primary.c
...
> @@ -114,7 +115,7 @@ check_digit (int c, int radix)
>        break;
> 
>      case 16:
> -      r = ('0' <= c && c <= '9') || ('a' <= c && c <= 'f');
> +      r = ISXDIGIT (c);
>        break;

This replacement is correct, i.e. it doesn't change the meaning, because the
content of c will not be uppercase here.

- Tobi