Well, thanks to the Arduino copyright problems, I can't see the products page that you linked. I'm in the USA so it forces me to see the USA version of the store, which doesn't seem to have the GSM shield listed. (I am pleased to see that it lists the Teensy3.2 right under the Uno.)
Anyway... that function (macro actually) digitalPinToPCICR() is defined in the variant.h file for each individual type of Arduino board. The mapping of pin to interrupt is different for each different processor, you see. But maybe it's missing for the Arduino Robot board?
I'm running Arduino 1.6.2 and I've got two "boards" for the robot. Both of them have the same error. At least the problem is reproducible. Here's the code I'm using to show the error. This is the complete sketch. It's not intended to do anything except be compiled.
void setup() {
// put your setup code here, to run once:
volatile uint8_t* x = digitalPinToPCICR(2);
}
void loop() {
// put your main code here, to run repeatedly:
}
I'll look into the variant file for the robot board next. Stand by...
Strange. The Arduino Robot uses the same processor as the Leonardo and the Mini. All the pin mappings seem to be identical, so why did they "forget" to copy that part over?
Try this... put the code below into your file, above any #include lines. See if that fixes the problem.
If that does fix it, then you can proceed with your project. If you want to make it a more permanent fix, then put those lines into your own pins_arduino.h file, which is unfortunately rather deeply buried in the Arduino installation on your computer.
The GSM shield is using software serial. On the Micro/Leonardo/Robot, you can use hardware serial instead. That may avoid a few problems. That processor only has a restricted list of pins available to be used for the receive function of software serial. Most other Arduinos have no restriction.
I think your next problem is going to be the GSM shield is using a pin that the Robot can't use for SoftwareSerial. You can only have Rx on pins 8, 9, 10, 11, 14, 15, 16 and it seems like most of those are already used on the Robot.