[gtk+] gdk: Ensure resources registration happens once

[Emmanuele Bassi <ebassi src gnome org>]

commit 0e14456f15412b1245cc8dab7df7021793d44441
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Apr 26 09:10:03 2016 +0100

    gdk: Ensure resources registration happens once
    
    Like GTK does it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765576

 gdk/gdk.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdk.c b/gdk/gdk.c
index 6c7464c..97ea213 100644
--- a/gdk/gdk.c
+++ b/gdk/gdk.c
@@ -269,6 +269,22 @@ gdk_add_option_entries_libgtk_only (GOptionGroup *group)
   gdk_add_option_entries (group);
 }
 
+static gpointer
+register_resources (gpointer dummy G_GNUC_UNUSED)
+{
+  _gdk_register_resource ();
+
+  return NULL;
+}
+
+static void
+gdk_ensure_resources (void)
+{
+  static GOnce register_resources_once = G_ONCE_INIT;
+
+  g_once (&register_resources_once, register_resources, NULL);
+}
+
 void
 gdk_pre_parse (void)
 {
@@ -277,7 +293,7 @@ gdk_pre_parse (void)
 
   gdk_initialized = TRUE;
 
-  _gdk_register_resource ();
+  gdk_ensure_resources ();
 
   /* We set the fallback program class here, rather than lazily in
    * gdk_get_program_class, since we don't want -name to override it.