gcompat: gtk_widget_set_can_focus() for below 2.18

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/gcompat.h b/gcompat.h
index 61b9894..8b8461a 100644
--- a/gcompat.h
+++ b/gcompat.h
@@ -39,4 +39,8 @@
 #define GFIO_DRAW_EVENT		"expose_event"
 #endif
 
+#if GTK_MAJOR_VERSION <= 2 && GTK_MINOR_VERSION < 18
+void gtk_widget_set_can_focus(GtkWidget *widget, gboolean can_focus);
+#endif
+
 #endif