[OpenMP,Fortran] Fix several OpenMP use_device_addr/map/update errors

[OpenMP,Fortran] Fix several OpenMP use_device_addr/map/update errors

	gcc/fortran/
	* f95-lang.c (LANG_HOOKS_OMP_IS_ALLOCATABLE_OR_PTR): Re-define to
	gfc_omp_is_allocatable_or_ptr.
	* trans-decl.c (create_function_arglist): Set GFC_DECL_OPTIONAL_ARGUMENT
	only if not passed by value.
	* trans-openmp.c (gfc_omp_is_allocatable_or_ptr): New.
	(gfc_trans_omp_clauses): For MAP, handle (present) optional arguments;
	for target update, handle allocatable/pointer scalars.
	* trans.h (gfc_omp_is_allocatable_or_ptr): Declare.

	gcc/
	* langhooks-def.h (LANG_HOOKS_OMP_IS_ALLOCATABLE_OR_PTR): Define.
	(LANG_HOOKS_DECLS): Add it.
	* langhooks.h (lang_hooks_for_decls): Add omp_is_allocatable_or_ptr;
	update comment for omp_is_optional_argument.
	* omp-general.c (omp_is_allocatable_or_ptr): New.
	* omp-general.h (omp_is_allocatable_or_ptr): Declare.
	* omp-low.c (scan_sharing_clauses, lower_omp_target): Handle
	Fortran's optional arguments and allocatable/pointer scalars
	with use_device_addr.

	libgomp/
	* testsuite/libgomp.fortran/use_device_addr-1.f90: New.
	* testsuite/libgomp.fortran/use_device_addr-2.f90: New.

From-SVN: r276875