Ping [patch, fortran] Remove some wrong unused warnings, do not issue warnings if there are errors.

[Thomas Koenig]

Am 19.06.26 um 17:37 schrieb Thomas Koenig:

Ping?

https://gcc.gnu.org/pipermail/fortran/2026-June/064145.html

the attached patch implements the discussion about not issuing
the new warnings if there are previous errors, and also fixes two
cases where wrong warnings were issued.

Regression-tested.

OK for trunk?

... I will of course remove

     * gfortran.dg/warn_unused_but_set_error_1.s: New test.

from the patch before it is committed (left over from testing).

Best regards

        Thomas