gcc/fortran/
	* dump-parse-tree.c (show_omp_clauses): Handle optional num and static
	arguments for the gang clause.
	* gfortran.h (gfc_omp_clauses): Rename gang_expr as gang_num_expr.
	Add gang_static_expr.
	* openmp.c (gfc_free_omp_clauses): Update to free gang_num_expr and
	gang_static_expr.
	(match_oacc_clause_gang): Update to support both num and static in
	the same clause.
	(resolve_omp_clauses): Formatting.  Also handle gang_num_expr and
	gang_static_expr.
	(resolve_oacc_params_in_parallel): New const char arg argument.
	Use it to report more accurate gang, worker and vector clause errors.
	(resolve_oacc_loop_blocks): Update calls to
	resolve_oacc_params_in_parallel.
	* trans-openmp.c (gfc_trans_omp_clauses): Update the gimplification of
	the gang clause.
	(gfc_trans_oacc_combined_directive): Make use of gang_num_expr and
	gang_static_expr.  Remove OMP_LIST_REDUCTION from construct_clauses.

	gcc/testsuite/
	* gfortran.dg/goacc/gang-static.f95: Add tests for gang num arguments.
	* gfortran.dg/goacc/loop-2.f95: Update expected diagnostics.
	* gfortran.dg/goacc/loop-6.f95: Likewise.
	* gfortran.dg/goacc/loop-7.f95: New test.
	* gfortran.dg/goacc/reduction-2.f95: New test.

From-SVN: r231112