The undefined behavior sanitizer complains about unaligned
loads, even if they're OK for a particular platform in
practice. It's possible that they _are_ a problem, of
course, but since it's a known tradeoff the UBSan errors are
just noise.
Let's quiet it automatically by building with
NO_UNALIGNED_LOADS when SANITIZE=undefined is in use.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>