[gofrtran] Fix PR 16465: accept -ffixed-line-length-72

[Tobias Schlüter]

Toon Moene wrote:
> 
> Not so fast - this is fixed form code, so every line is 72 characters 
> long.  g77 was quite innovative in treating this right - IIRC, DEC 
> changed its compiler to match g77's behaviour.
> 

I've updated my patch. But before I post it, I want to know: Is support
for arbitrary line lengths with --fixed-line-length-none also a must, or
is the builtin maximum of 132 ok? I just don't want to do that work
unnecessarily.

For writing a testcase, I'm interested in this: is there a way to
compile and run a testcase with several different options, and expect
different output each time, i.e.
	character(400) :: t
        t=
       1"
       2a"
        print *, len_trim(t)+6
        end
has this behavior:
option --ffixed-line-length-72   -> prints: 72
option --ffixed-line-length-132  -> prints: 132
option --ffixed-line-length-none -> prints: 7
etc.

- Tobi