Hello,
I want to program Attiny84 using Arduino Uno as ISP, but can not find proper library. I used to program Attiny85 using attiny45_85.zip This library does contain also Attiny84, however not to be programmed with Arduino as ISP. I found other libraries, like arduino-tiny-0100-0016.zip, but they too do not provide choice of Attiny84 to be programmed with Arduino as ISP. Can anyone help?
Downloaded the newest file from the link provided (arduino-tiny-0150-0020.zip), but it still does not contain a choice on Arduino IDE at Tools-Board for Attiny84 w/Arduino as ISP. It contains only Attiny84 (internal oscilator; BOD disabled) with different MHz options. 
You don't actually have to have a chip to test that.
In Tools > Programmer, you should be able to select "Arduino as ISP" with Tools > Board > "ATtiny84 ..." selected.
Good, let us know if it solves your issue 
