race condition in dinput's multiple joystick code and IL2

[H. Verbeet]

I didn't look at the threading issue, but there is at least one part
of that patch that looks wrong to me:

In joydev_enum_deviceW():
>-  if (id != 0)
>-      return FALSE;
>+  if (id >= have_joydevs) {
>+    return -1;
>+  }
I think that should return FALSE rather than -1 (TRUE).