add cpu detection code

[shawnl]

it looks like you wrote the cpu detection code in openssl. It would be nice if that stuff (which is important for using these routines) was here, so the license was clearer.

[noloader]

Google has a library called cpu_features. It is missing a few key defines and platforms, like ARMv7 and PowerPC. You will certainly want ARMv7 for ARM builds. It is a good start, though.

You should be able to map cpu features to OpenSSL/Cryptogams defines with the use of grep.