* gimplify.c (gimplify_omp_ordered): Fix up diagnostics
	wording.
	* omp-low.c (check_omp_nesting_restrictions): Update for the
	various new OpenMP 4.5 nesting restrictions, clarified
	nesting glossary, closely nested region relationship clarified
	to mean explicit or implicit parallel regions (target/teams),
	use %</%> or %qs where appropriate.

	* gcc.dg/gomp/ordered-2.c (f1): Expect an extra error.
	* g++.dg/gomp/ordered-2.C (f1): Likewise.
	* gfortran.dg/goacc/parallel-kernels-regions.f95: Adjust
	expected diagnostics for the addition of quotes.
	* gfortran.dg/gomp/target3.f90: Likewise.
	* c-c++-common/goacc/nesting-fail-1.c: Likewise.
	* c-c++-common/goacc-gomp/nesting-fail-1.c: Likewise.
	* c-c++-common/gomp/doacross-1.c: Likewise.
	* c-c++-common/gomp/nesting-warn-1.c: Likewise.
	* c-c++-common/gomp/cancel-1.c (f2): Add some new tests.
	Adjust expected diagnostics wording.
	* c-c++-common/gomp/clauses-4.c (foo): Likewise.
	Don't expect error on ordered threads simd when in for simd.
	* c-c++-common/gomp/nesting-2.c: New test.
	* c-c++-common/gomp/ordered-3.c (foo): Add some new tests.
	* c-c++-common/gomp/ordered-4.c: New test.

From-SVN: r229892