[gtk+] Suppress cursor theme unsupported warning when there's no theme.

[John Ralls <jralls src gnome org>]

commit 108c20bd5112509b9ff2bc11ba698137e50f4e11
Author: John Ralls <jralls ceridwen us>
Date:   Thu Oct 10 15:35:41 2013 -0700

    Suppress cursor theme unsupported warning when there's no theme.

 gtk/gtksettings.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtksettings.c b/gtk/gtksettings.c
index a163f17..aabc1bb 100644
--- a/gtk/gtksettings.c
+++ b/gtk/gtksettings.c
@@ -2697,7 +2697,8 @@ settings_update_cursor_theme (GtkSettings *settings)
                 "gtk-cursor-theme-name", &theme,
                 "gtk-cursor-theme-size", &size,
                 NULL);
-
+  if (theme == NULL)
+    return;
 #ifdef GDK_WINDOWING_X11
   if (GDK_IS_X11_DISPLAY (display))
     gdk_x11_display_set_cursor_theme (display, theme, size);