bg pixmap fix with xsun

[jacob berkman <jacob ximian com>]

this patch fixes a BadMatch error with gtk 2.0, and a failed g_return
assertion on 2.2.

is it right?  do we want to make a new pixmaps or something?

it's nice to finally be able to have nautilus do the desktop stuff on
solaris after having nautilus crash for the last n months every time.

 - jacob

Index: nautilus-directory-background.c
===================================================================
RCS file: /cvs/gnome/nautilus/libnautilus-private/nautilus-directory-background.c,v
retrieving revision 1.79
diff -u -r1.79 nautilus-directory-background.c
--- nautilus-directory-background.c	25 Jun 2002 20:06:43 -0000	1.79
+++ nautilus-directory-background.c	12 Jul 2002 18:51:52 -0000
@@ -544,7 +544,8 @@
 	set_root_pixmap (pixmap);
 
 	background_window = background_get_desktop_background_window (background);
-	if (background_window != NULL) {
+	if (background_window != NULL &&
+            gdk_drawable_get_depth (window) == gdk_drawable_get_depth (pixmap))
 		gdk_window_set_back_pixmap (background_window, pixmap, FALSE);
 	}