OpenACC reference count consistency checking

OpenACC reference count consistency checking

2018-11-28  Julian Brown  <julian@codesourcery.com>
	    Tobias Burnus  <tobias@codesourcery.com>

	libgomp/
	* libgomp.h (RC_CHECKING): New macro, disabled by default, guarding all
	hunks in this patch.
	(target_mem_desc): Add forward declaration.
	(async_tgt_use): New struct.
	(target_mem_desc): Add refcount_chk, mark fields.
	(acc_dispatch_t): Add tgt_uses, au_lock fields.
	(dump_tgt, gomp_rc_check): Add prototypes.
	* oacc-async (goacc_async_unmap_tgt): Add refcount self-check code.
	(goacc_async_copyout_unmap_vars): Likewise.
	(goacc_remove_var_async): Likewise.
	* oacc-parallel.c (GOACC_parallel_keyed_internal): Add refcount
	self-check code.
	(GOACC_data_start, GOACC_data_end, GOACC_enter_exit_data): Likewise.
	* target.c (stdio.h): Include.
	(dump_tgt, rc_check_clear, rc_check_count, rc_check_verify)
	(gomp_rc_check): New functions to consistency-check reference counts.
	(gomp_target_init): Initialise self-check-related device fields.