[gnome-screensaver] Fix compiling with GSeal. Fixes bug #612551.

[Andre Klapper <aklapper src gnome org>]

commit c669b01e7f10122191ff9c24e7999a652b071dcf
Author: Andre Klapper <a9016009 gmx de>
Date:   Sun Jun 27 10:51:09 2010 +0200

    Fix compiling with GSeal. Fixes bug #612551.

 savers/gste-slideshow.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/savers/gste-slideshow.c b/savers/gste-slideshow.c
index e520251..b436078 100644
--- a/savers/gste-slideshow.c
+++ b/savers/gste-slideshow.c
@@ -182,7 +182,11 @@ start_fade (GSTESlideshow *show,
                                                              256,
                                                              color,
                                                              color);
+#if GTK_CHECK_VERSION (2,21,1)
+                pixmap = gdk_pixmap_new (NULL, ph, pw,  gdk_visual_get_depth (gdk_visual_get_system ()));
+#else
                 pixmap = gdk_pixmap_new (NULL, ph, pw,  gdk_visual_get_system ()->depth);
+#endif
 
                 gdk_draw_pixbuf (pixmap, NULL, colored, 0, 0, 0, 0, -1, -1, GDK_RGB_DITHER_MAX, 0, 0);
                 gdk_pixbuf_get_from_drawable (pixbuf, pixmap, NULL, 0, 0, 0, 0, -1, -1);