PR: 2432
Submitted by: Michael Heyman

add ghash benchmark to apps/speed.c.

in gcm_ghash_4bit. Taking the idea a step further I've added extra
256+16 bytes of per-key storage, so that one can speak about 3rd variant
in addition to "256B" and "4KB": "528B" one. Commonly it should be
~50% faster than "256B" implementation or ~25% slower than "4KB" one.

- gcm128.c: support for Intel PCLMULQDQ, readability improvements;
- asm/ghash-x86.pl: splitted vanilla, MMX, PCLMULQDQ subroutines;
- asm/ghash-x86_64.pl: add PCLMULQDQ implementations.

- introduce common modes_lcl.h;
- ctr128.c: implement additional CRYPTO_ctr128_encrypt_ctr32 interface;
- gcm128.c: add omitted ARM initialization, remove ctx.ctr;

ghash-x86*.pl: fix performance numbers for Core2, as it turned out
previous ones were "tainted" by variable clock frequency.

change.

subject to change...