Since NO_OPENSSL is no longer defined on Windows, BLK_SHA1 is not defined
anymore implicitly. Define it explicitly.
As a nice side-effect, we no longer link against libcrypto.dll, which has
non-trivial startup costs because it depends on 6 otherwise unneeded
DLLs.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>