Move the OpenACC enter and exit data directives from using a single builtin to
having one each.  For most purposes it was easy to tell which was which, from
the clauses given, but it's overhead we can easily avoid, and there may be
future uses where that isn't possible.

	gcc/
	* omp-builtins.def (BUILT_IN_GOACC_ENTER_EXIT_DATA): Split into...
	(BUILT_IN_GOACC_ENTER_DATA, BUILT_IN_GOACC_EXIT_DATA): ... these.
	* gimple.h (enum gf_mask): Split
	'GF_OMP_TARGET_KIND_OACC_ENTER_EXIT_DATA' into
	'GF_OMP_TARGET_KIND_OACC_ENTER_DATA' and
	'GF_OMP_TARGET_KIND_OACC_EXIT_DATA'.
	(is_gimple_omp_oacc): Update.
	* gimple-pretty-print.c (dump_gimple_omp_target): Likewise.
	* gimplify.c (gimplify_omp_target_update): Likewise.
	* omp-expand.c (expand_omp_target, build_omp_regions_1)
	(omp_make_gimple_edges): Likewise.
	* omp-low.c (check_omp_nesting_restrictions, lower_omp_target):
	Likewise.
	gcc/testsuite/
	* c-c++-common/goacc-gomp/nesting-fail-1.c: Adjust patterns.
	* c-c++-common/goacc/finalize-1.c: Likewise.
	* c-c++-common/goacc/mdc-1.c: Likewise.
	* c-c++-common/goacc/nesting-fail-1.c: Likewise.
	* c-c++-common/goacc/struct-enter-exit-data-1.c: Likewise.
	* gfortran.dg/goacc/attach-descriptor.f90: Likewise.
	* gfortran.dg/goacc/finalize-1.f: Likewise.
	* gfortran.dg/goacc/mapping-tests-3.f90: Likewise.
	libgomp/
	* libgomp.map (GOACC_2.0.2): New symbol version.
	* libgomp_g.h (GOACC_enter_data, GOACC_exit_data) New prototypes.
	* oacc-mem.c (GOACC_enter_data, GOACC_exit_data) New functions.

Co-Authored-By: Thomas Schwinge <thomas@codesourcery.com>