fix several locks that weren't updated right for new futex-based __lock

these could have caused memory corruption due to invalid accesses to
the next field. all should be fixed now; I found the errors with fgrep
-r '__lock(&', which is bogus since the argument should be an array.

src/thread/pthread_kill.c

@@ -3,8 +3,8 @@
 int pthread_kill(pthread_t t, int sig)
 {
 	int r;
-	__lock(&t->killlock);
+	__lock(t->killlock);
 	r = t->dead ? ESRCH : -__syscall(SYS_tgkill, t->pid, t->tid, sig);
-	__unlock(&t->killlock);
+	__unlock(t->killlock);
 	return r;
 }