* gthr.h: Document __GTHREAD_MUTEX_INIT_FUNCTION.
        * frame.c (init_object_mutex): New function.
        (init_object_mutex_once): Likewise.
        (find_fde): Call it.
        (__register_frame_info): Likewise.
        (__register_frame_info_table): Likewise.
        (__deregister_frame_info): Likewise.

From-SVN: r22023