Fortran/OpenMP: Add parsing support for allocators/allocate directives

Fortran/OpenMP: Add parsing support for allocators/allocate directives

gcc/fortran/ChangeLog:

	* dump-parse-tree.cc (show_omp_namelist): Update allocator, fix
	align dump.
	(show_omp_node, show_code_node): Handle EXEC_OMP_ALLOCATE.
	* gfortran.h (enum gfc_statement): Add ST_OMP_ALLOCATE and ..._EXEC.
	(enum gfc_exec_op): Add EXEC_OMP_ALLOCATE.
	(struct gfc_omp_namelist): Add 'allocator' to 'u2' union.
	(struct gfc_namespace): Add omp_allocate.
	(gfc_resolve_omp_allocate): New.
	* match.cc (gfc_free_omp_namelist): Free 'u2.allocator'.
	* match.h (gfc_match_omp_allocate, gfc_match_omp_allocators): New.
	* openmp.cc (gfc_omp_directives): Uncomment allocate/allocators.
	(gfc_match_omp_variable_list): Add bool arg for
	rejecting listening common-block vars separately.
	(gfc_match_omp_clauses): Update for u2.allocators.
	(OMP_ALLOCATORS_CLAUSES, gfc_match_omp_allocate,
	gfc_match_omp_allocators, is_predefined_allocator,
	gfc_resolve_omp_allocate): New.
	(resolve_omp_clauses): Update 'allocate' clause checks.
	(omp_code_to_statement, gfc_resolve_omp_directive): Handle
	OMP ALLOCATE/ALLOCATORS.
	* parse.cc (in_exec_part): New global var.
	(check_omp_allocate_stmt, parse_openmp_allocate_block): New.
	(decode_omp_directive, case_exec_markers, case_omp_decl,
	gfc_ascii_statement, parse_omp_structured_block): Handle
	OMP allocate/allocators.
	(verify_st_order, parse_executable): Set in_exec_part.
	* resolve.cc (gfc_resolve_blocks, resolve_codes): Handle
	allocate/allocators.
	* st.cc (gfc_free_statement): Likewise.
	* trans.cc (trans_code): Likewise.
	* trans-openmp.cc (gfc_trans_omp_directive): Likewise.
	(gfc_trans_omp_clauses, gfc_split_omp_clauses): Update for
	u2.allocator, fix for u.align.

libgomp/ChangeLog:

	* testsuite/libgomp.fortran/allocate-4.f90: Update dg-error.

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/allocate-2.f90: Update dg-error.
	* gfortran.dg/gomp/allocate-4.f90: New test.
	* gfortran.dg/gomp/allocate-5.f90: New test.
	* gfortran.dg/gomp/allocate-6.f90: New test.
	* gfortran.dg/gomp/allocate-7.f90: New test.
	* gfortran.dg/gomp/allocators-1.f90: New test.
	* gfortran.dg/gomp/allocators-2.f90: New test.