[PR90048] Fortran OpenACC 'private' clause rejected for predetermined private loop iteration variable

	gcc/fortran/
	PR fortran/90048
	* openmp.c (gfc_resolve_do_iterator): Handle sharing_clauses for
	OpenACC, too.
	(gfc_resolve_oacc_blocks): Populate sharing_clauses with private
	clauses.
	gcc/testsuite/
	PR fortran/90048
	* gfortran.dg/goacc/private-explicit-kernels-1.f95: New file.
	* gfortran.dg/goacc/private-explicit-parallel-1.f95: Likewise.
	* gfortran.dg/goacc/private-explicit-routine-1.f95: Likewise.

From-SVN: r270406