[gimp-perl] set_transient no-op if no UI.

[Ed J <edj src gnome org>]

commit 7d6eb8d482341738d9f49afb09eea3d61f905537
Author: Ed J <edj src gnome org>
Date:   Wed Jun 18 21:15:09 2014 +0100

    set_transient no-op if no UI.

 UI/UI.xs |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/UI/UI.xs b/UI/UI.xs
index 0315c65..3d770aa 100644
--- a/UI/UI.xs
+++ b/UI/UI.xs
@@ -143,7 +143,8 @@ void
 set_transient(window)
   GtkWindow *window
   CODE:
-    gimp_window_set_transient (window);
+    if (gimp_display_name())
+      gimp_window_set_transient (window);
 
 gint32
 export_image(image_ID, drawable_ID, format_name, capabilities)