This happens at least since July 4th.

android-container-nyc-4877805-r1: >>> Compiling source in /build/newbie/tmp/portage/chromeos-base/android-container-nyc-4877805-r1/work ...
android-container-nyc-4877805-r1:  * ERROR: chromeos-base/android-container-nyc-4877805-r1::cheets-private failed (compile phase):
android-container-nyc-4877805-r1:  *   unknown architecture
android-container-nyc-4877805-r1:  * 
android-container-nyc-4877805-r1:  * Call stack:
android-container-nyc-4877805-r1:  *     ebuild.sh, line 133:  Called src_compile
android-container-nyc-4877805-r1:  *   environment, line 807:  Called die
android-container-nyc-4877805-r1:  * The specific snippet of code:
android-container-nyc-4877805-r1:  *           die "unknown architecture";