[gfortran] gfortran options and cc1 warnings

[FX Coudert]

>>  What should "gfortran -fdollar-ok a.f b.c" do, if -fdollar-ok if a 
>> fortran-only option?
> 
> It shouldn't pass -fdollar-ok to cc1, IMHO.

I'm not sure about how other languages handle that. Trying to mix java 
and C gives:

$ gcj -c Example.java a.c -Wredundant-modifiers
cc1: warning: command line option "-Wredundant-modifiers" is valid for 
Java but not for C

So, I guess we need to align on that...

FX