See the tinderbox log attached to bug #332287 — almost unreadable because of colour escape codes. Having an option to ignore colours like portage-utils has it would make possible for Portage to pass it when NOCOLOR=1 is set in make.conf as it is for the tinderbox.
the framework is already in place to support this via portage-utils. it's just stubbed to 1 all the time. paxinc.h:#define color 1
support added to pspax/scanelf/scanmacho in cvs