PR libfortran/20660
    * io/inquire.c (inquire_via_unit): Non-opened units should still be
    reported by an INQUIRE statement as existing.
    * io/transfer.c (data_transfer_init): Never accept negative units.

    PR libfortran/20660
    * gfortran.dg/negative_unit.f: New test.

From-SVN: r97326