march values for newer architectures like westmere, which are those where clang would probably be especially popular due to "better support", are breaking with clang from 9-CURRENT though, while clang from llvm-trunk can build working -march=corei7-avx binaries (although AVX is still not enabled by default).
Of cause FreeBSD is in beta state, but a contrib merge isn't likely to become a big deal, and other rather large changes were commited during beta, too (e.g. capricom).
