I successfully implemented x20r in cpuminer-multi

Source can be found here:

https://github.com/hashfaster/cpuminer-multi

AMD GPU wildrig: https://github.com/andru-kun/wildrig-multi/releases/tag/0.13.5

Tested on pool, solved a block even, even better!

MINERS
cpuminer: https://github.com/hashfaster/cpuminer-multi
NVIDIA ccminer: https://github.com/hashfaster/ccminer-x20r
AMD wildrig: https://github.com/hashfaster/wildrig-multi/releases/tag/0.13.5
-a x20r -o stratum+tcp://hashfaster.com:20070 -u WALLET -p c=ASTRAL