stumped here.
Created attachment 443812 [details] /var/log/genkernel.log
Created attachment 443814 [details] emerge --info
I'm having exactly the same issue with genkernel-3.5.0.4 (busybox build failure). genkernel-3.5.0.2 works fine.
It happened again. Kernel version being compiled: gentoo-sources-4.7.2
Created attachment 444668 [details, diff] patch to fix a typo causing this issue
Created attachment 444670 [details, diff] one more typo fix
This is already fixed in 3.5.0.5