[gnome-shell] st: Bail out on clipboard requests if there is no text.

[Carlos Garnacho <carlosg src gnome org>]

commit eaec459ee98e3b216a945f3198256036cfe927bb
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Oct 10 19:12:27 2014 +0200

    st: Bail out on clipboard requests if there is no text.
    
    If a selection request happens through foreign means, the selected
    text is NULL, and a crash happens.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=738314

 src/st/st-clipboard.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/st/st-clipboard.c b/src/st/st-clipboard.c
index a09360d..32da142 100644
--- a/src/st/st-clipboard.c
+++ b/src/st/st-clipboard.c
@@ -119,7 +119,8 @@ st_clipboard_provider (GdkXEvent *xevent_p,
   XSelectionRequestEvent *req_event;
   GdkDisplay *display = gdk_display_get_default ();
 
-  if (xev->type != SelectionRequest)
+  if (xev->type != SelectionRequest ||
+      !clipboard->priv->clipboard_text)
     return GDK_FILTER_CONTINUE;
 
   req_event = &xev->xselectionrequest;