On a machine with Ubuntu 16.04 and 2 intel CPUs.
EDIT: see post at the end. Apparently I can’t get Julia running on the other CPU on this machine. So the real question is how to build Julia on a machine with two physical CPUs?
First without override ARCH=x86_64 in Make.user  I always get ERROR: Target architecture mismatch. Please delete or regenerate sys.{so,dll,dylib}.
Anyways, no problem there with the override in the Make.user file override ARCH=x86_64  julia  builds and runs fine.
However running make test keeps spitting  ERROR: Target architecture mismatch. Please delete or regenerate sys.{so,dll,dylib}.  Any help here?
Running julia  - no problem
Running   julia test/runtests.jl all spits:
$ julia --check-bounds=yes test/runtests.jl all
ERROR: Target architecture mismatch. Please delete or regenerate sys.{so,dll,dylib}.
ERROR: Target architecture mismatch. Please delete or regenerate sys.{so,dll,dylib}.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.
exiting.
Master process (id 1) could not connect within 60.0 seconds.