openacc: Strided array sections and components of derived-type arrays

openacc: Strided array sections and components of derived-type arrays

This patch disallows selecting components of array sections in update
directives for OpenACC, as specified in OpenACC 3.0, "2.14.4. Update
Directive":

  In Fortran, members of variables of derived type may appear, including
  a subarray of a member. Members of subarrays of derived type may
  not appear.

The diagnostic for attempting to use the same construct on other
directives has also been improved.

gcc/fortran/
	* openmp.c (resolve_omp_clauses): Disallow selecting components
	of arrays of derived type.

gcc/testsuite/
	* gfortran.dg/goacc/array-with-dt-2.f90: Remove expected errors.
	* gfortran.dg/goacc/array-with-dt-6.f90: New test.
	* gfortran.dg/goacc/mapping-tests-2.f90: Update expected error.
	* gfortran.dg/goacc/ref_inquiry.f90: Update expected errors.
	* gfortran.dg/gomp/ref_inquiry.f90: Likewise.

libgomp/
	* testsuite/libgomp.oacc-fortran/array-stride-dt-1.f90: Remove
	expected errors.