Source can be found here:
https://github.com/hashfaster/cpuminer-multi
precompiled ubuntu binary:
https://github.com/hashfaster/cpuminer-multi/releases/download/v1.3.5-multi-x20r/cpuminer-ubuntu-x64-static.tar.gz
Tested on pool, solved a block even, even better!
cpuminer -a x20r -o stratum+tcp://hashfaster.com:20070 -u WALLETADDRESS -p c=ASTRAL
./cpuminer -a x20r -o stratum+tcp://hashfaster.com:20070 -u AFzxxxxxxxxxxxxxxxxxxxxxxxxxxxx -p c=ASTRAL
** cpuminer-multi 1.3.5 by tpruvot@github **
BTC donation address: 1FhDPLPpw18X4srecguG3MxJYe4a1JsZnd (tpruvot)
[2018-12-02 12:30:52] Starting Stratum on stratum+tcp://hashfaster.com:20070
Illegal instruction
I see this error