Fortran/OpenMP: align/allocator modifiers to the allocate clause

gcc/fortran/ChangeLog:

	* dump-parse-tree.cc (show_omp_namelist): Improve OMP_LIST_ALLOCATE
	output.
	* gfortran.h (struct gfc_omp_namelist): Add 'align' to 'u'.
	(gfc_free_omp_namelist): Add bool arg.
	* match.cc (gfc_free_omp_namelist): Likewise; free 'u.align'.
	* openmp.cc (gfc_free_omp_clauses, gfc_match_omp_clause_reduction,
	gfc_match_omp_flush): Update call.
	(gfc_match_omp_clauses): Match 'align/allocate modifers in
	'allocate' clause.
	(resolve_omp_clauses): Resolve align.
	* st.cc (gfc_free_statement): Update call
	* trans-openmp.cc (gfc_trans_omp_clauses): Handle 'align'.

libgomp/ChangeLog:

	* libgomp.texi (5.1 Impl. Status): Split allocate clause/directive
	item about 'align'; mark clause as 'Y' and directive as 'N'.
	* testsuite/libgomp.fortran/allocate-2.f90: New test.
	* testsuite/libgomp.fortran/allocate-3.f90: New test.