ui/gtk: Fix callback function signature

The correct type for opaque pointer is gpointer,
not gpointer * (which is a pointer to a pointer).

Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

ui/gtk.c

@@ -766,9 +766,9 @@ static gboolean gd_render_event(GtkGLArea *area, GdkGLContext *context,
 }
 
 static void gd_resize_event(GtkGLArea *area,
-                            gint width, gint height, gpointer *opaque)
+                            gint width, gint height, gpointer opaque)
 {
-    VirtualConsole *vc = (void *)opaque;
+    VirtualConsole *vc = opaque;
     double pw = width, ph = height;
     double sx = vc->gfx.scale_x, sy = vc->gfx.scale_y;
     GdkWindow *window = gtk_widget_get_window(GTK_WIDGET(area));