I am having a hard time keeping up.
First there was a LCD problem with IDE 1.5.4
Then the LCD works on another arduino board.
Then your arduino had only 3.3 volts on the 5 volt pin.
Now you get Compile errors when you use a RTC shield.
Lets slow down. The last thing I mentioned was that you had a problem with your power supply ( 5v). Have you got that fixed yet.
I use a 5 V DC power supply connected to VIN now and got stable conditions on the shield.
. I don't really know what that means. Do you read 5.1 Volts on the 5volt pin now?
I am sorry for the hard time ;-)
The Yun is new for me and has some changes.
Your hint to the rigth power supply was very good and helped to get clear conditions on the shield. I have 4.6 V on pin 5V due to the voltage drop over D2. This is ok for me.
Now I have two problems furthermore:
1. The LCD Keypad shield - may be more complex
2. Therefore I was going one step back and tried a simple I2C sensor DS1307. This work on Arduino 2009 & IDE 1.0.5 but not with Yun & IDE 1.5.4.
I saw the changed pinout of the Yun. This is one issue I have not realized (:-)) and I think with the correct pins this will be ok. Sorry for that.
Not clear is the compiler error described.