If a widget has a width/height of 0, we can safely draw it without running out
of the available space. This code checks if we got enough space after we now how
much space the next widget wants.
This fixes the systray. It has to be drawn at least once so that the C core can
set up stuff correctly. However, thanks to the systray having a width of 0, it
wasn't drawn by the layout.
Signed-off-by: Uli Schlachter <psychon@znc.in>
Uli Schlachter