In

/var/git/meta-repo/kits/core-kit/profiles/funtoo/1.0/linux-gnu/arch/x86-64bit/subarch/intel64-broadwell/make.defaults

there is no

CPU_FLAGS_X86="..."

entry, which is present in other subarches, like e.g. intel64-haswell.

I noticed this because my ego sync today, followed by a @world update emerge wanted to recompile lots of packages that had previously been compiled with the proper cpu flags.