MakeMask         1497 butteraugli.cc                 MakeMask(extmul, extoff, mul, offset, scaler);
MakeMask         1509 butteraugli.cc       MakeMask(extmul, extoff, mul, offset, scaler);
MakeMask         1521 butteraugli.cc       MakeMask(extmul, extoff, mul, offset, scaler);
MakeMask         1533 butteraugli.cc       MakeMask(extmul, extoff, mul, offset, scaler);