Disable sse4_2

kallikrates/iktinos lack this, they're opteron 6128s. 
2 jobs for master in 105 minutes and 26 seconds (queued for 110 minutes and 11 seconds)
Status Job ID Name Coverage
  Build
passed #170425241
lineage-builder triggered
build

01:32:36

 
  Sign
passed #170425242
signing-proxy triggered
sign

00:12:49