Flexelint on Linux exhibits exactly the problem described by phk in
his rant at the top of vsa.c, quote:

	Do I need to tell you that static code analysis tools have a
	really hard time coping with (struct suckaddr_storage), and
	that they give a lot of false negatives which confuse people ?

One instance of this issue:

--- Module:   cache/cache_acceptor.c (C)
                                               _
 #... _assert(!!((getsockname(sp->fd, (void*)&ss, &sl)) == 0)) /*lint -restore *
 #... getsockname(sp->fd, (void*)&ss, &sl)) == 0); } while (0)
	AZ(getsockname(sp->fd, (void*)&ss, &sl));
cache/cache_acceptor.c  330  Error 64: Type mismatch (arg. no. 2) (union
    __SOCKADDR_ARG = void *)
                                 _
 #... SA_Build(sa, &ss, sl)) != 0); } while (0)
	AN(VSA_Build(sa, &ss, sl));
cache/cache_acceptor.c  332  Warning 603: Symbol 'ss' (line 318) not
    initialized
cache/cache_acceptor.c  318  Info 830: Location cited in prior message
                                                                  _
			i = accept(ls->sock, (void*)&wa.acceptaddr,
cache/cache_acceptor.c  458  Error 64: Type mismatch (arg. no. 2) (union
    __SOCKADDR_ARG = void *)

There is one more in cache/cache_backend_probe.c

As the purpose of VSA is to avoid exactly this kind of trouble, we
provide a VSA-wrapper for getsockname.