[Bug fortran/66765] gfortran passing fortran-specific options to ld and collect2

["dje at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66765

--- Comment #9 from David Edelsohn <dje at gcc dot gnu.org> ---
> [Book15] f90/bug% gcc ya_sincos.c -fdump-fortran-original
> cc1: error: unrecognized command line option '-fdump-fortran-original'

This is a valid Fortran option producing an error from cc1 when passed to gcc.

but

> [Book15] f90/bug% gcc ya_sincos.c -fblah-blah
> gcc: error: unrecognized command line option '-fblah-blah'

This is an invalid command line option for any GCC front-end and evokes an
error from gcc.  I'm not sure what you are trying to prove.

> nothing to do with gfortran FE, and

> [Book15] f90/bug% gcc ya_sincos.c -fdefault-integer-8
> cc1: warning: command line option '-fdefault-integer-8' is valid for Fortran but not for C

Some errors are caught with a more user-friendly error message.  I don't see
what any of this proves.

The Fortran FE is the only place that can differentiate between gfortran
command line options and c-family command line options.