backgraph.c, gc_priv.h (GC_traverse_back_graph, [...]): split GC_traverse_back_graph.

	* backgraph.c, gc_priv.h (GC_traverse_back_graph,
	GC_print_back_graph_stats): split GC_traverse_back_graph.
	* backgraph.c: Dynamically grow in_progress_space.
	* finalize.c (GC_notify_or_invoke_finalizers): also call
	GC_print_back_graph_stats.
	* alloc.c, finalize.c, gc_priv.h (GC_generate_random_backtrace_no_gc,
	GC_print_back_height): Move delarations to header file.
	* configure.ac: rename --enable-full-debug to --enable-gc-debug.
	* configure: Regenerate.

From-SVN: r86685