library: Add option to register additional namespaces before calling library_init()

Because settings are already accessed in library_init(), calling
add_fallback() externally after calling library_init() is not ideal.
This way namespaces already serve as fallback while library_init() is
executed and they are also in the correct order so that libstrongswan is
always the last root section.

src/libstrongswan/library.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2014 Tobias Brunner
+ * Copyright (C) 2010-2016 Tobias Brunner
  * Copyright (C) 2008 Martin Willi
  * Hochschule fuer Technik Rapperswil
  *
@@ -276,4 +276,14 @@ void library_deinit();
  */
 extern library_t *lib;
 
+/**
+ * Add additional names used as alias for the namespace registered with
+ * library_init().
+ *
+ * To be called from __attribute__((constructor)) functions.
+ *
+ * @param ns			additional namespace
+ */
+void library_add_namespace(char *ns);
+
 #endif /** LIBRARY_H_ @}*/