/*
 *  call-seq:
 *     dir.make_lock(lock_name) -> self
 *
 *  Make a lock with the name +lock_name+. Note that lockfiles will be stored
 *  in the directory with other files but they won't be visible to you. You
 *  should avoid using files with a .lck extension as this extension is
 *  reserved for lock files
 */
static VALUE
frt_dir_make_lock(VALUE self, VALUE rlock_name)
{
    VALUE rlock;
    Lock *lock;
    Store *store = DATA_PTR(self);
    StringValue(rlock_name);
    lock = open_lock(store, rs2s(rlock_name));
    rlock = Data_Wrap_Struct(cLock, &frt_lock_mark, &frt_lock_free, lock);
    object_add(lock, rlock);
    return rlock;
}