title: Teensy as keyboard: error: 'keyboard_leds' was not declared in this scope
body: <p>I'm new to Teensy, and I'm trying to write a program that allows it to act as a keyboard. To make my program more useful, I'd like to make it not try to act on any input until its drivers install. I saw on GitHub that a way to do this (assuming the user doesn't hit it themselves) is to instruct the program to hit caps lock until the LED turns on. The function I wrote looks like this:</p>
  
  <pre><code>void waitForInstall(){
      boolean currCaps = keyboard_leds;
      while ((currCaps &amp; 2) == (keyboard_leds &amp; 2)){
          delay(200);
          Keyboard.set_key1(KEY_CAPS_LOCK);
          Keyboard.send_now();
      }
  }
  </code></pre>
  
  <p>When I try to compile this, Arduino IDE informs me that <code>'keyboard_leds' was not declared in this scope</code>. I'm sure I made a very basic mistake, but would anyone mind humoring me and giving me a push in the right direction? Thanks! </p>