* omp-low.c (struct omp_context): Remove gwv_below, gwv_this
	fields.
	(is_oacc_parallel, is_oacc_kernels): New.
	(enclosing_target_ctx): May return NULL.
	(ctx_in_oacc_kernels_region): New.
	(check_oacc_kernel_gwv): New.
	(oacc_loop_or_target_p): Delete.
	(scan_omp_for): Don't calculate gwv mask.  Check parallel clause
	operands.  Strip reductions fro kernels.
	(scan_omp_target): Don't calculate gwv mask.
	(lower_oacc_head_mark, lower_oacc_loop_marker,
	lower_oacc_head_tail): New.
	(struct oacc_collapse): New.
	(expand_oacc_collapse_init, expand_oacc_collapse_vars): New.
	(expand_omp_for_static_nochunk, expand_omp_for_static_chunk):
	Remove OpenACC handling.
	(expand_oacc_for): New.
	(expand_omp_for): Call expand_oacc_for.
	(lower_omp_for): Call lower_oacc_head_tail.

From-SVN: r229472