Now message can look like:
[xwayland/xwm.c:991] xcb error: op ChangeProperty (no minor), code Window (no extension), value 6291465
instead of this one when the lib is not available:
[xwayland/xwm.c:999] xcb error: op 18:0, code 3, sequence 103, value 6291465
The value in case of Window is the window id, so we can tell what
function applied on which window which is a good start.
The sequence ought to be able to tell us more precisely which
invocation it was, but we never log it when calling functions
so is useless in practice and no longer logged.
We move the warning options into the project's default_options, meaning
a user can configure them with `meson configure` and not need to edit
the file.
We also make it possible to disable logind/libcap even if they're
present.
