I'm confused. I am attempting to write a small sketch that uses the tiny85 and its interrupt system. I have my IDE setup to work with the tiny85 and an ISP and this works fine. The problem I'm having is just how to refer to the pins on the tiny85. For example. In the AVR docs Pin 7 is labeled "PB2 (SCK/USCK/SCL/ADC1/T0/INT0/PCINT). If I want to use that pin as an I/O pin I refer to it as PB2. If I want to connect an external interrupt to it do I refer to it as INT0 or PB2. Where are these defined?
I'm not sure what you mean by 'core' but this is what I have. Arduino 1.5.4 usbtinyisp w32 driver v1.12 attiny downloaded from GitHub in the hardware directory of my Arduino IDE.
I also have the Atmel Studio 6.1 and the Atmel STK600 that seem to work fine. I use that for the ATMega2560 programming. I also have MS Visual Studio 2012 and Visual Micro that I use to program my other Arduino boards.