This facilitates "universal" builds, ones that target multiple
architectures, e.g. ARMv5 through ARMv7. See commentary in
Configure for details.
Reviewed-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>

Improve decrypt performance by 10-20% depending on platform. Thanks
to Jussi Kivilinna for providing valuable hint. Also thanks to Ard
Biesheuvel.

Suggested by: Ard Biesheuvel

Submitted by: Ard Biesheuvel

Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>

Submitted by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Contributor claims ~50% improvement in CTR and ~9% in CBC decrypt
on Cortex-A15.

insignificant, it's actually 4 cycles less for 14 instructions sequence!

reference implementation, it does not interface to OpenSSL yet.