protothreads-library
There are 3 repositories under protothreads-library topic.
Akagi201/protothreads
my fork of http://dunkels.com/adam/pt/index.html
jumbleview/pumpkin
Example of using Adam Dunkels protothreads while programming Attiny85 chip.
ar2rus/PTTasker
Another one Protothreads (PT) library for ESP8266 Arduino