Very nice Erni, pictures help so much.
For the Tiny13A wiring.c just needs the string added in below.
|| (__AVR_ATtiny13__)
From this,
#if defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
SIGNAL(TIM0_OVF_vect)
#else
SIGNAL(TIMER0_OVF_vect)
#endif
To this,
#if defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || (__AVR_ATtiny13__)
SIGNAL(TIM0_OVF_vect)
#else
SIGNAL(TIMER0_OVF_vect)
#endif
When I opened the file up in notepad, it was very tricky to find, all the text run horizontally. It was a nightmare, but if you know what to look out for it's still tricky. In the end I just to used word.
Pasted as (Keep text Only). Oh yes! Be sure to make a copy off the original, if you FUBAR it you can role back with the original!!
My file was located here,
C:\Arduino\arduino-1.0.3\hardware\arduino\cores\arduino
This tut is good, newb's like me will struggle, some parts are vague.. I still don't know what "fuse bytes" are or what they are used for. I had disregard it all but plugged away...