Fix a classic programmer bug, spotted by the increasingly eagle-eyed

LLVM C-compiler.

You have no idea how much or how long (20+ years!) I have missed having
an alternative to GCC.

Remember:

  Mono cultures are particularly bad for you, when they are good for you

Kudos to:       The LLVM team.

bin/varnishtest/vtc_varnish.c

@@ -206,7 +206,7 @@ varnish_thread(void *priv)
 	(void)VTCP_nonblocking(v->fds[0]);
 	while (1) {
 		fds = &fd;
-		memset(fds, 0, sizeof fds);
+		memset(fds, 0, sizeof *fds);
 		fds->fd = v->fds[0];
 		fds->events = POLLIN;
 		i = poll(fds, 1, 1000);