openmp: Disable strided target updates when iterators are used

openmp: Disable strided target updates when iterators are used

Non-contiguous target updates result in the new strided target updates code
being used, resulting in new clauses such as GOMP_MAP_GRID_DIM,
GOMP_MAP_GRID_STRIDE etc. These are not currently supported in conjunction
with iterators, so this code-path is disabled when used together with
iterators.

The older target updates supports non-contiguous updates as long as a stride
is not applied.

gcc/c/

	* c-typeck.cc (handle_omp_array_sections): Add extra argument.  Set
	argument to true if array section has a stride that is not one.
	(c_finish_omp_clauses): Disable strided updates when iterators are
	used in the clause.  Emit sorry	if strided.

gcc/cp/

	* semantics.cc (handle_omp_array_sections): Add extra argument.  Set
	argument to true if array section has a stride that is not one.
	(finish_omp_clauses): Disable strided updates when iterators are
	used in the clause.  Emit sorry if strided.

gcc/fortran/

	* trans-openmp.cc (gfc_trans_omp_clauses): Disable strided updates
	when iterators are used in the clause.