gcompat: get closer to working with gtk3

Just need the draw event now, instead of the expose_event.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/gcompat.c b/gcompat.c
index f691ec1..7b0810b 100644
--- a/gcompat.c
+++ b/gcompat.c
@@ -33,3 +33,17 @@
 }
 
 #endif
+
+#if GTK_MAJOR_VERSION < 3
+
+guint gtk_widget_get_allocated_width(GtkWidget *w)
+{
+	return w->allocation.width;
+}
+
+guint gtk_widget_get_allocated_height(GtkWidget *w)
+{
+	return w->allocation.height;
+}
+
+#endif