* decl.c (struct binding_level): Add GTY marker. Compile
	binding_depth unconditionally.
	(current_binding_level, free_binding_level, global_binding_level):
	Likewise.
	(clear_binding_level): Unconditionally set binding_depth.
	(make_binding_level): Use ggc_alloc_cleared, not xmalloc.

From-SVN: r82323