First batch of the alphabet.

Change-Id: If4e60f4fbb69e04eb4b70aa1b2240e329251bfa5
Reviewed-on: https://boringssl-review.googlesource.com/4514
Reviewed-by: Adam Langley <agl@google.com>

Found while diagnosing some crashes and hangs in the malloc tests. This (and
the follow-up) get us further but does not quite let the malloc tests pass
quietly, even without valgrind. DTLS silently ignores some malloc failures
(confusion with silently dropping bad packets) which then translate to hangs.

Change-Id: Ief06a671e0973d09d2883432b89a86259e346653
Reviewed-on: https://boringssl-review.googlesource.com/3482
Reviewed-by: Adam Langley <agl@google.com>

Everything before crypto/ec.

Change-Id: Icbfab8e4ffe5cc56bf465eb57d3fdad3959a085c
Reviewed-on: https://boringssl-review.googlesource.com/3401
Reviewed-by: Adam Langley <agl@google.com>

This is an initial cut at aarch64 support. I have only qemu to test it
however—hopefully hardware will be coming soon.

This also affects 32-bit ARM in that aarch64 chips can run 32-bit code
and we would like to be able to take advantage of the crypto operations
even in 32-bit mode. AES and GHASH should Just Work in this case: the
-armx.pl files can be built for either 32- or 64-bit mode based on the
flavour argument given to the Perl script.

SHA-1 and SHA-256 don't work like this however because they've never
support for multiple implementations, thus BoringSSL built for 32-bit
won't use the SHA instructions on an aarch64 chip.

No dedicated ChaCha20 or Poly1305 support yet.

Change-Id: Ib275bc4894a365c8ec7c42f4e91af6dba3bd686c
Reviewed-on: https://boringssl-review.googlesource.com/2801
Reviewed-by: Adam Langley <agl@google.com>

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)