Fortran : rejected f0.d edit descriptor PR96436

Fortran  : rejected f0.d edit descriptor PR96436

Zero length f format descriptors are valid for Fortran 95 and
later.  For g format descriptors from Fortran 2008 and later.
Finally for D, E, EN and ES for Fortran 2018 and later.

2020-08-20  Mark Eggleston  <markeggleston@gcc.gnu.org>

libgfortran/

	PR fortran/96436
	* io/format.c (parse_format_list):  Add new local variable
	"standard" to hold the required standard to check. If the
	format width is zero select standard depending on descriptor.
	Call notification_std using the new standard variable.

2020-08-20  Mark Eggleston  <markeggleston@gcc.gnu.org>

gcc/testsuite/

	PR fortran/96436
	* gfortran.dg/pr96436_1.f90: New test.
	* gfortran.dg/pr96436_2.f90: New test.
	* gfortran.dg/pr96436_3.f90: New test.
	* gfortran.dg/pr96436_4.f90: New test.
	* gfortran.dg/pr96436_5.f90: New test.
	* gfortran.dg/pr96436_6.f90: New test.
	* gfortran.dg/pr96436_7.f90: New test.
	* gfortran.dg/pr96436_8.f90: New test.
	* gfortran.dg/pr96436_9.f90
	* gfortran.dg/pr96436_10.f90