Prefer /etc/portage/make.profile.

Prefer /etc/portage/make.profile.

This is the default location used by current versions of eselect
profile, and will soon be the default location in stages. Since
eselect profile generates a warning if both /etc/make.profile and
/etc/portage/make.profile exist, the new default should be fairly
safe (although eselect profile currently prefers /etc/make.profile
when both exist).