This is the portage make.conf that I used.

myPortageMake.conf (text/plain), 733 bytes, created by John Stein on 2016-05-24 13:27:31 UTC

# These settings were set by the catalyst build script that automatically
# built this stage.
# Please consult /usr/share/portage/config/make.conf.example for a more
# detailed example.
CFLAGS="-march=native -O2 -pipe"
CXXFLAGS="${CFLAGS}"
# WARNING: Changing your CHOST is not something that should be done lightly.
# Please consult http://www.gentoo.org/doc/en/change-chost.xml before changing.
CHOST="x86_64-pc-linux-gnu"
# These are the USE flags that were used in addition to what is provided by the
# profile used for building.
USE="alsa usb"
PORTDIR="/usr/portage"
DISTDIR="${PORTDIR}/distfiles"
PKGDIR="${PORTDIR}/packages"
MAKEOPTS="-j5"

GENTOO_MIRRORS="http://ftp.ucsb.edu/pub/mirrors/linux/gentoo/"
VIDEO_CARDS="nouveau"