Previously the WGL winsys was expecting the application to send all
windows messages to Cogl via the cogl_win32_renderer_handle_event
function. When using a GLib main loop we can make this work
transparently to the application with a GSource for the magic
G_WIN32_MSG_HANDLE file descriptor. That causes the GMainLoop to wake
up whenever a message is available.
This patch makes the WGL winsys add that magic value as a source fd.
This will only have any meaning if the application is using glib, but
it shouldn't matter because the cogl_poll_renderer_get_info function
is documented to only work on Unix-based winsys's anyway.
This patch is an API break because by default Cogl will now start
stealing all of the Windows messages. Something like Clutter that wants to handle
its own event retrieval would now need to call
cogl_win32_renderer_set_event_retrieval_enabled to stop Cogl from
stealing the events.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 99a7f84d7149f24f3e86c5d3562f9f2632ff6df8)
4543ed6ac3