Sorry, there was a change in 1.0.2 that is incompatible with processors that don't have hardware serial support (like the ATtiny). This will be fixed in 1.0.3. See: Issues with Arduino 1.0.2 · Issue #8 · damellis/attiny · GitHub. For now, you can use 1.0.1 or change:
#error TXC0 not definable in HardwareSerial.h
to:
#warning TXC0 not definable in HardwareSerial.h
in HardwareSerial.h.