CL 106235 removed runtime.support_avx on which blake2b depends to determine AVX support. Switch to use the corresponding feature flags from internal/cpu instead. While at it, also use AVX2 and SSE4 (for Go 1.7 and later) from there. Change-Id: I4f7a27fcfa0c5d0d7a50444c7aa32519b97e90dd Reviewed-on: https://go-review.googlesource.com/106336 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>