old-makefile: add options.lua

Also, make use of generic rules.
old-build: fix building with libquvi4
x11: add a generic function for NetWM state setting

And use it for fullscreening. It will also be used for fixing --ontop.
x11: fix NetWM ontop setting

I can only assume the old code was wrong. EWMH does not document
anything with _WIN_LAYER. Instead, you have to toggle the state using a
client message. We also remove these weird non-sense fallbacks, like
using _NET_WM_STATE_BELOW - what the hell?
x11: rename identifiers using reserved namespace

You can't use identifiers starting with "_" and an uppercase letter in
application programs. They are reserved by the C standard.

Unrelated change: drop unused/misleading vo_wm_NETWM define.
x11: prefer NetWM hints over _WIN_LAYER for --ontop

_WIN_LAYER is apparently an old GNOME thing (also explains why there is
a function vo_x11_get_gnome_layer() involved in this code). Prefer the
NetWM hints over this. This just moves the NetWM case if-body over the
_WIN_LAYER one.
x11: un-inline GNOME layer stuff

Having it as separate function is not useful.

Also remove the useless vo_window parameter.