Okay, so everyone who had any interest in my new Attiny841 core immediately asked about 1.6.x support.
So I got it working on 1.6.0 pretty easy. Figured I should drop 1.0.6 since it doesn't seem possible to make one core that works with both due to changes in boards.txt.
Trying to keep up with the times, I removed 1.60, deleted Arduino user folder, installed 1.6.2, and tried to reinstall my core. And nothing works.
My custom core used to work on 1.6.0.
On 1.6.2, I get:
Cannot run program "C:\Arduino/hardware/tools/avr/bin/avr-g++": CreateProcess error=2, The system cannot find the file specified
Sure enough - the compiler toolchain is GONE!
Where the hell is it now, and how do I get my core to work again?
The core migration guide makes no mention of this!
Core is this one - https://github.com/SpenceKonde/arduino-tiny-841 - this used to work (at least for the 841 - didn't yet test the 1634 - that was one of the things I was about to do, when I discoverd that the toolchain was no longer accessible.