Add private api to load a single module

In the following commits, this function will be used to load the
gtkparasite module.

gtk/gtkmodules.c

@@ -600,3 +600,10 @@ _gtk_module_has_mixed_deps (GModule *module_to_check)
 
   return result;
 }
+
+void
+_gtk_modules_load_module (const gchar *name)
+{
+  /* We leak the ref */
+  g_slist_free (load_modules (name));
+}

gtk/gtkmodules.h

@@ -49,7 +49,6 @@ typedef void     (*GtkModuleInitFunc)        (gint        *argc,
  */
 typedef void     (*GtkModuleDisplayInitFunc) (GdkDisplay   *display);
 
-
 G_END_DECLS
 
 

gtk/gtkmodulesprivate.h

@@ -38,6 +38,7 @@ void     _gtk_modules_init             (gint          *argc,
                                         const gchar   *gtk_modules_args);
 void     _gtk_modules_settings_changed (GtkSettings   *settings,
                                         const gchar   *modules);
+void     _gtk_modules_load_module      (const gchar   *name);
 
 gboolean _gtk_module_has_mixed_deps    (GModule       *module);