Binutils 2.20 does not support avx/avx2 instructions.
It appears the earliest version of Binutils with avx2 support is v2.22 which was released in November 2011.
This binutils appears to come from RedHat or Centos EL 6 which is just too old for development work.
RHEL/CentOS 7 isn’t much better, but it has a new enough binutils. I’d recommend upgrading.