re PR c++/5571 (crash in initialization of a static variable)

	PR c++/5571
	* stor-layout.c (layout_decl): Reset the RTL for the decl.

	* class.c (layout_class_type): Remember incomplete static
	variables.
	(finish_struct_1): Call complete_vars, not
	hack_incomplete_structures.
	* cp-tree.h (hack_incomplete_structures): Rename to ...
	(complete_vars): ... this.
	(struct saved_scope): Remove incomplete.
	(namespace_scope_incomplete): Remove.
	* decl.c (struct binding_level): Remove incomplete.
	(incomplete_vars): New variable.
	(mark_binding_level): Don't mark incomplete.
	(print_binding_level): Don't print it.
	(mark_saved_scope): Don't mark incomplete.
	(pushdecl): Use maybe_register_incopmlete_var.
	(cxx_init_decl_processing): Register incomplete_vars for GC.
	(start_decl_1): Clarify error message.
	(hack_incomplete_vars): Remove.
	(maybe_register_incomplete_var): New function.
	(complete_vars): Likewise.

	* g++.dg/opt/static2.C: New test.

From-SVN: r51978