Create a buffer for events with input devices connected.
Creates an event buffer and attaches all input devices
with matching capabilities. If no input devices match,
e.g. by specifying DICAPS_NONE, a buffer will be returned
that has no event sources connected to it.
If global is DFB_FALSE events will only be delivered if this
instance of IDirectFB has a focused primary (either running fullscreen
or running in windowed mode with the window being focused).
If global is DFB_TRUE no event will be discarded.