hellange/arduino — pull request #1 by PaulStoffregen (2014-07-24 20:03:28+00:00)
Title: Use digitalPinToInterrupt on newer versions of Arduino

Newer versions of Arduino have a #define for digitalPinToInterrupt(), to convert pin numbers to interrupt numbers for attachInterrupt. This tiny patch will make your code compatible with all future boards, regardless of their pin-to-interrupt mapping, and it will fall back to your original approach when used on older versions of Arduino.